Answer:
B. the mean
Step-by-step explanation:
According to the Bar Chart shown, the number of DVDs sold at a local music store during one week are displayed.
Therefore, the measure(s) of central tendency that can be used to determine the average number of DVDs sold each day is the mean.
This is because the mean is the sum total of the number of DVDs sold, divided by the number, which gives the average.
Answer:
The Mean
Step-by-step explanation:
I took the test
Describe the motion of a particle with position (x, y) as t varies in the given interval. (For each answer, enter an ordered pair of the form x, y.) x = 1 + sin(t), y = 3 + 2 cos(t), π/2 ≤ t ≤ 2π
Answer:
The motion of the particle describes an ellipse.
Step-by-step explanation:
The characteristics of the motion of the particle is derived by eliminating [tex]t[/tex] in the parametric expressions. Since both expressions are based on trigonometric functions, we proceed to use the following trigonometric identity:
[tex]\cos^{2} t + \sin^{2} t = 1[/tex] (1)
Where:
[tex]\cos t = \frac{y-3}{2}[/tex] (2)
[tex]\sin t = x - 1[/tex] (3)
By (2) and (3) in (1):
[tex]\left(\frac{y-3}{2} \right)^{2} + (x-1)^{2} = 1[/tex]
[tex]\frac{(x-1)^{2}}{1}+\frac{(y-3)^{2}}{4} = 1[/tex] (4)
The motion of the particle describes an ellipse.
rewrite 1/6 and 2/11 so they have a common denominator then use <, =, or > to order
Answer:
1/6 < 2/11
Step-by-step explanation:
1/6 = 2/12
2/11 >2/12
So that means 1/6 < 2/11
Answer: 1/6 < 2/11
This is the same as saying 11/66 < 12/66
===========================================================
Explanation:
1/6 is the same as 11/66 when multiplying top and bottom by 11.
2/11 is the same as 12/66 when multiplying top and bottom by 6.
The 6 and 11 multipliers are from the original denominators (just swapped).
We can see that 11/66 is smaller than 12/66, simply because 11 < 12, so that means 1/6 is smaller than 2/11
-----------------
Here's one way you could list out the steps
11 < 12
11/66 < 12/66
1/6 < 2/11
------------------
Here's another way to list out the steps. First assume that 1/6 and 2/11 are equal. Cross multiplication then leads to
1/6 = 2/11
1*11 = 6*2
11 = 12
Which is false. But we can fix this by replacing every equal sign with a less than sign
1/6 < 2/11
1*11 < 6*2
11 < 12
---------------------
Yet another way to see which is smaller is to use your calculator or long division to find the decimal form of each value
1/6 = 0.1667 approximately
2/11 = 0.1818 approximately
We see that 0.1667 is smaller than 0.1818, which must mean 1/6 is smaller than 2/11.
hey Plz help me fast it's important.
Answer:
Step-by-step explanation:
a) 52 is divisible by 4 and 5 - 2 = 3
b) 63 is divisible by 9 and 3*2 = 6 -> ten digit
c) 50 is divisible by 10 and 5 + 0 = 5
d) 72 is divisible by 6 and 7*2 = 14
what is the best deal for diet coke?
12oz. for $.99
64oz. for $.2.99
128oz. for $4.99
Answer:
128 for 4.99
64 for 2.99 times 2 is more than 4.99.
12 oz. for 0.99 is also more than 4.99.
A game-show spinner has these odds of stopping on particular dollar values: 55% for $5, 20% for $25, 15% for $50, and 10% for $500. What are the odds of a player winning $5 or $25
Answer: 75%
Step-by-step explanation:
HELP PLEASE! I tried everything from adding to dividing, subtracting, multiplying but still no correct answer. Can someone help me out here please? I am not sure where to start. Thank you for your time.
Answer:
6.09 is the answer rounded to nearest hundredths.
Step-by-step explanation:
It gives you n=150, p=0.55, and q=1-p.
If p=0.55 and q=1-p, then by substitution property we have q=1-0.55=0.45.
It ask you to evaluate the expression sqrt(npq).
So npq means find the product of 150 and 0.55 and 0.45. So that is 150(0.55)(0.45)=37.125.
The sqrt(npq) means we need to find the square root of that product. So sqrt(37.125)=6.093 approximately .
4x-1,9x-1,7x-3 find the perimeter
20x-5
Answer:
Solution given;
perimeter=sum of all sides
=4x-1+9x-1+7x-3=20x-5
The perimeter of the line segments 4x - 1, 9x - 1, and 7x - 3 is 20x - 5.
To find the perimeter of the given line segments, you need to add up the lengths of all the line segments.
The lengths of the line segments are:
4x - 1,
9x - 1,
7x - 3.
To find the perimeter, add these lengths together:
Perimeter = (4x - 1) + (9x - 1) + (7x - 3)
= 4x + 9x + 7x - 1 - 1 - 3
= 20x - 5.
Therefore, the perimeter of the line segments 4x - 1, 9x - 1, and 7x - 3 is 20x - 5.
To learn more on Perimeter click:
https://brainly.com/question/7486523
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solve 5x^2-2=-12 by taking the square root
Answer:
x = ±i√2
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightEquality Properties
Multiplication Property of Equality
Division Property of Equality
Addition Property of Equality
Subtraction Property of Equality
Algebra II
Imaginary root i
i = √-1Step-by-step explanation:
Step 1: Define
Identify
5x² - 2 = -12
Step 2: Solve for x
[Addition Property of Equality] Add 2 on both sides: 5x² = -10[Division Property of Equality] Divide 5 on both sides: x² = -2[Equality Property] Square root both sides: x = ±√-2Rewrite: x = ±√-1 · √2Simplify: x = ±i√2In a survey, 24 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $42 and standard deviation of $2. Construct a confidence interval at a 98% confidence level.
Answer:
The 98% confidence interval for the mean amount spent on their child's last birthday gift is between $40.98 and $43.02.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 24 - 1 = 23
98% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 23 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.98}{2} = 0.99[/tex]. So we have T = 2.5
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.5\frac{2}{\sqrt{24}} = 1.02[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 42 - 1.02 = $40.98.
The upper end of the interval is the sample mean added to M. So it is 42 + 1.02 = $43.02.
The 98% confidence interval for the mean amount spent on their child's last birthday gift is between $40.98 and $43.02.
a car travels 10 km southeast and 15 km in a direction 60 degrees north of east. find the magnitude and direction
Answer:
the car travels 10km then 15km 60* north of east
Step-by-step explanation:
Two lamps marked 100 W - 110 V and 100 W - 220 V are connected i
series across a 220 V line. What power is consumed in each lamp?
The power consumed in the lamp marked 100W - 110V is 15.68W
The power consumed in the lamp marked 100W - 220V is 62.73W
Step-by-step explanation:
Given:
First lamp rating
Power (P) = 100W
Voltage (V) = 110V
Second lamp rating
Power (P) = 100W
Voltage (V) = 220V
Source
Voltage = 220V
i. Get the resistance of each lamp.
Remember that power (P) of each of the lamps is given by the quotient of the square of their voltage ratings (V) and their resistances (R). i.e
P = [tex]\frac{V^2}{R}[/tex]
Make R subject of the formula
⇒ R = [tex]\frac{V^2}{P}[/tex] ------------------(i)
For first lamp, let the resistance be R₁. Now substitute R = R₁, V = 110V and P = 100W into equation (i)
R₁ = [tex]\frac{110^2}{100}[/tex]
R₁ = 121Ω
For second lamp, let the resistance be R₂. Now substitute R = R₂, V = 220V and P = 100W into equation (i)
R₂ = [tex]\frac{220^2}{100}[/tex]
R₂ = 484Ω
ii. Get the equivalent resistance of the resistances of the lamps.
Since the lamps are connected in series, their equivalent resistance (R) is the sum of their individual resistances. i.e
R = R₁ + R₂
R = 121 + 484
R = 605Ω
iii. Get the current flowing through each of the lamps.
Since the lamps are connected in series, then the same current flows through them. This current (I) is produced by the source voltage (V = 220V) of the line and their equivalent resistance (R = 605Ω). i.e
V = IR [From Ohm's law]
I = [tex]\frac{V}{R}[/tex]
I = [tex]\frac{220}{605}[/tex]
I = 0.36A
iv. Get the power consumed by each lamp.
From Ohm's law, the power consumed is given by;
P = I²R
Where;
I = current flowing through the lamp
R = resistance of the lamp.
For the first lamp, power consumed is given by;
P = I²R [Where I = 0.36 and R = 121Ω]
P = (0.36)² x 121
P = 15.68W
For the second lamp, power consumed is given by;
P = I²R [Where I = 0.36 and R = 484Ω]
P = (0.36)² x 484
P = 62.73W
Therefore;
The power consumed in the lamp marked 100W - 110V is 15.68W
The power consumed in the lamp marked 100W - 220V is 62.73W
Which statement best describes g(x) = 3x + 6 - 8 and the parent function f(x) = } ?
The domains of g(x) and f(x) are the same, but their ranges are not the same.
* The ranges of g(x) and f(x) are the same, but their domains are not the same.
The ranges of g(x) and f(x) are the same, and their domains are also the same.
The domains of g(x) and f(x) are the not the same, and their ranges are also not the same.
Answer:
In general gf(x) is not equal to fg(x)
Some pairs of functions cannot be composed. Some pairs of functions can be composed only for certain values of x.
Only with they can be composed some values of x are the ranges of g(x) and f(x) are the same, and their domains are also the same. Or else lies inside it.
Step-by-step explanation:
g(x) = 3x + 6 - 8, f(x) = √x.
The domain of a composed function is either the same as the domain of the first function, or else lies inside it
The range of a composed function is either the same as the range of the second function, or else lies inside it.
Or vice versa
Now only positive numbers, or zero, have real square roots. So g is defined only for numbers
greater than or equal to zero. Therefore g(f(x)) can have a value only if f(x) is greater than or
equal to zero. You can work out that
f(x) ≥ 0 only when x ≥3/2
.
Find domain of (x^2+3)+[tex]\sqrt{x} 3x-1[/tex]
Answer:
= x^2 + 3 + √3x^2 - 1
Step-by-step explanation:
Remove parentheses: (a) = a
= x^2 + 3 + √x . 3x - 1
x . 3x = 3x^2
= x^2 + 3 + √3x^2 - 1
A hotel manager believes that 23% of the hotel rooms are booked. If the manager is right, what is the probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%
Answer:
0.9216 = 92.16% probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
A hotel manager believes that 23% of the hotel rooms are booked.
This means that [tex]p = 0.23[/tex]
Sample of 610 rooms
This means that [tex]n = 610[/tex]
Mean and standard deviation:
[tex]\mu = p = 0.23[/tex]
[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.23*0.77}{610}} = 0.017[/tex]
What is the probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%?
p-value of Z when X = 0.23 + 0.03 = 0.26 subtracted by the p-value of Z when X = 0.23 - 0.03 = 0.2. So
X = 0.26
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.26 - 0.23}{0.017}[/tex]
[tex]Z = 1.76[/tex]
[tex]Z = 1.76[/tex] has a p-value of 0.9608
X = 0.2
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.2 - 0.23}{0.017}[/tex]
[tex]Z = -1.76[/tex]
[tex]Z = -1.76[/tex] has a p-value of 0.0392
0.9608 - 0.0392 = 0.9216
0.9216 = 92.16% probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%
Javier volunteers in community events each month. He does not do more than five events in a month. He attends exactly five events 25% of the time, four events 30% of the time, three events 20% of the time, two events 15% of the time, one event 5% of the time, and no events 5% of the time. Find the probability that Javier volunteers for less than three events each month. P (x < 3) = 2 Find the expected number of events Javier volunteers in a month. 3.6 It is given that x must be below a certain value, which limits the rows to use in the PDF table. What is the sum of the probabilities of those rows?
Answer:
[tex]P(x < 3) = 25\%[/tex]
[tex]E(x) = 3[/tex]
Step-by-step explanation:
The given parameters can be represented as:
[tex]\begin{array}{ccccccc}x & {5} & {4} & {3} & {2} & {1}& {0} & P(x) & {25\%} & {30\%} & {20\%} & {15\%} & {5\%} & {5\%} \ \end{array}[/tex]
Solving (a): P(x < 3)
This is calculated as:
[tex]P(x < 3) = P(x = 0) + P(x = 1) + P(x =2)[/tex] ----- i.e. all probabilities less than 3
So, we have:
[tex]P(x < 3) = 5\% + 5\% + 15\%[/tex]
[tex]P(x < 3) = 25\%[/tex]
Solving (b): Expected number of events
This is calculated as:
[tex]E(x) = \sum x * P(x)[/tex]
So, we have:
[tex]E(x) = 5 * 25\% + 4 * 30\% + 3 * 20\% + 2 * 15\% + 1 * 5\% + 0 * 5\%[/tex]
[tex]E(x) = 125\% + 120\% + 60\% + 30\% + 5\% + 0\%[/tex]
[tex]E(x) = 340\%[/tex]
Express as decimal
[tex]E(x) = 3.40[/tex]
Approximate to the nearest integer
[tex]E(x) = 3[/tex]
The Blacktop Speedway is a supplier of automotive parts. Included in stock are 7 speedometers that are correctly calibrated and two that are not. Three speedometers are randomly selected without replacement. Let the random variable z represent the number that are not correctly calibrated.
Complete the probability distribution table. (Report probabilities accurate to 4 decimal places.)
x P(x)
0
1
2
3
Answer:
x P(x)
0 0.4167
1 0.5
2 0.0833
3 0
Step-by-step explanation:
The speedometers are chosen without replacement, which means that the hypergeometric distribution is used to solve this question.
Hypergeometric distribution:
The probability of x successes is given by the following formula:
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
In which:
x is the number of successes.
N is the size of the population.
n is the size of the sample.
k is the total number of desired outcomes.
In this question:
7 + 2 = 9 speedometers, which means that [tex]N = 9[/tex]
2 are not correctly calibrated, which means that [tex]k = 2[/tex]
3 are chosen, which means that [tex]n = 3[/tex]
Complete the probability distribution table.
Probability of each outcome.
So
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
[tex]P(X = 0) = h(0,9,3,2) = \frac{C_{2,0}*C_{7,3}}{C_{9,3}} = 0.4167[/tex]
[tex]P(X = 1) = h(1,9,3,2) = \frac{C_{2,1}*C_{7,2}}{C_{9,3}} = 0.5[/tex]
[tex]P(X = 2) = h(2,9,3,2) = \frac{C_{2,2}*C_{7,1}}{C_{9,3}} = 0.0833[/tex]
Only 2 defective, so [tex]P(X = 3) = 0[/tex]
Probability distribution table:
x P(x)
0 0.4167
1 0.5
2 0.0833
3 0
There is a high-speed rail track between London and Manchester.
The length of this track is 210 miles.
A train departs London at 11:20 and arrives in Manchester at 13:28
The train company claims
the average speed of this train is 104 miles per hour.
Is the average speed of this train 104 miles per hour?
(4)
Use the box below to show clearly how you get your answer.
Answer:
Step-by-step explanation:
this is the famous dirt formula, :P I made it up :D
D=rt ( notice it looks like Dirt , kinda, but it also means it dirt simple )
D= distance
r = rate ( think speed or how fast)
t = time ( in what ever units of time you want to use, seconds, minutes, hours )
13:28 - 11:20 = 128 minutes ( b/c the question is asking in MPH convert to hours) 2.4666667 hours
210 miles = r * 2.46666667
210 / 2.46666667 = r ( in MPH) ( does anyone else find it odd that they are saying miles in London instead of kilometers? :/ )
85.135 MPH = rate
so no, not even close to 104 MPH :/
Answer:
Average speed is 98 mph
Step-by-step explanation:
[tex]\frac{distance (miles)}{time (hours)}[/tex] = speed [tex]\frac{mile}{hours}[/tex] (miles per hour is a ratio)
The time is 2 hours and 8 minutes.
[tex]\frac{8}{60}[/tex] = .13333 ( 8 minutes / 60 minutes in a hour)
So time is 2.133333 hours .
Divide the distance 210 by the time 2.13333 and get the speed.
Its 98.437..
Round to 98 miles per hour.
Juan and Lizette rented a car for one week to drive from Phoenix to Boise. The car rental rate was $250 per week and $0.20 per mile. By the most direct route, the drive is 926 miles. How much did they spend on the rental car?
( solution at pic)
find the slope of a line perpendicular to the line below. y=2x+4
Water lilies are often used to decorate ponds, as shown in the photo. But they are also famous for their unusual growth pattern!
Answer:
what is the question
pls mark me as brainlist
Thank you for the points
1. The area of a square is less than 25cm2. What can we say about
a. The length of one of its sides?
b. Its perimeter?
Step-by-step explanation:
Let us take a nominal square of area 25 cm².
It's length of one of it's sides will be √25 = 5 cm².It's perimeter will be 5*4 = 20 cm.So, in this question, we can say that:-
a. The length of one of its sides will be less than 5 cm.
b. Its perimeter will be less than 20 cm.
Hope it helps :)
Step-by-step explanation:
area= 25cm squared
length of one side = 5cm as 5*5 =25
perimeter= 5*4= 20cm
But since the area is less than 25cm squared
we can say that the length of one side is less than 5cm and we can also say that the length of the perimeter is less than 20cm.
Hope this helps.
The width of a rectangular slab of concrete is 7 m less than the length. The area is 98 m squared. Find the dimensions
Answer:
Length = 14 m, Width = 7 m
Step-by-step explanation:
Let the length is l and width is b.
Width, b = l-7
Area of the rectangle, A = 98 m²
We know that, the area of a rectangle is as follow :
[tex]A=lb[/tex]
So,
[tex]98=l(l-7)\\\\98=l^2-7l\\\\l^2-7l-98=0\\\\l^2+7l-14l-98=0\\\\l(l+7)-14(l+7)=0\\\\l=14,-7[/tex]
Length can't be negative. So,
Width, b = 14-7 = 7 m
So, the dimensions of the rectangle are 14 m and 7 m respectively.
Two mechanics worked on a car. The first mechanic worked for 10 hours, and the second mechanic worked for 5 hours. Together they charged a total of $1125. What was the rate charged per hour by each mechanic if the sum of the two rates was $140 per hour?
Answer:
The first mechanic charged $ 85 an hour, and the second mechanic charged $ 55 an hour.
Step-by-step explanation:
Given that two mechanics worked on a car, and the first mechanic worked for 10 hours, and the second mechanic worked for 5 hours, and together they charged a total of $ 1125, to determine what was the rate charged per hour by each mechanic if the sum of the two rates was $ 140 per hour, the following calculation must be performed:
1125/15 = X
75 = X
80 x 10 + 60 x 5 = 800 + 300 = 1100
85 x 10 + 55 x 5 = 850 + 275 = 1125
Therefore, the first mechanic charged $ 85 an hour, and the second mechanic charged $ 55 an hour.
HELPPP
3p-4-8p<-19
i need the steps as well
9514 1404 393
Answer:
p > 3
Step-by-step explanation:
3p -4 -8p < -19 . . . . . . given
-5p -4 < - 19 . . . . . . . . collect terms
-5p < -15 . . . . . . . . . . . add 4
p > 3 . . . . . . . . . . . . . . divide by -5 (reverses the inequality symbol)
Find the appropriate answer for each word problem.
a. A group of twelve art students are visiting a local art museum for a field trip. The total cost of admission for the students is $125. What is the cost of admission for each student?
b. The school van can carry twelve passengers at a time. What is the least number of trips the van must make in order to bring 125 passengers to the same location?
c. Charlotte and her mother baked 125 cookies to give as Christmas gifts to their neighbors. If they plan to give a dozen cookies to each neighbor, how many neighbors will receive a gift?
d. Nicholas and Elaine are planning to serve cheesecake for dessert at their wedding and have purchased twelve cheesecakes. If the cheesecakes are divided evenly among the 125 wedding guests, how much cheesecake will each guest receive?
I WILL GIVE BRAINLIEST IF CORRECT
Answer:
a. $10
b. 10.46
c. 10.46
d. 0.096
Gsggagsgsvhdgdvdvdvdvdg help me fast I’ll give you brainliste
The answer is D
Hope that was fast enough
Question A cotton farmer produced 390 pounds per acre after 4 years of operating. After 9 years, he was producing 460 pounds per acre. Assuming that the production amount has been increasing linearly, estimate the production per acre 7 years after he started farming. Your answer should just be a numerical value. Do not include units in your answer. Provide your answer below:
HELP! AAHHHHH SOMEBODY HELP!
If each square of the grid below is $0.5\text{ cm}$ by $0.5\text{ cm}$, how many square centimeters are in the area of the blue figure?
Answer:
8.50 cm²
Step-by-step explanation:
The dimension of each square is given as 0.5cm by 0.5cm
The area of the a square is, a²
Where, a = side length
Area of each square = 0.5² = 0.25cm
The number of blue colored squares = 34
The total area of the blue colored squares is :
34 * 0.25 = 8.50cm²
what are the zeroes of f(x)=(x-7)(x+8)
Answer:
The zeroes of f(x) = (x-7)(x+8) are 7 and -8.
Step-by-step explanation:
You have to figure out what makes each of the equal to zero.
Step 1 : Make the 2 equations both equal 0.
x-7 = 0
x+8 = 0
Step 2: Solve for x
x-7 = 0
x=7
x+8 = 0
x=-8
So 7 and -8 are both zeroes of this function.
h=255-21t-16t^2
PLEASE HELP!!
Answer:
3.15 seconds is the answer.
Explanation
when the ball touches the ground, h =0
hence,
0=255-21t-16t²
16t²+21t-225=0
here a=16 ,b=21, c= -225
[tex]t= \frac{ - b± \sqrt{ {b }^{2} - 4ac} }{2a} \\ \\ t= \frac{ - 21± \sqrt{ {21}^{2} - 4 \times 16 \times - 225} }{2 \times 16} \\ = \frac{ - 21 ± \sqrt{441 - ( - 14400)} }{32} \\ = \frac{ - 21± \sqrt{14841} }{32} \\ = \frac{ - 21±121.82}{32} \\ \\ t = \frac{ - 21 + 121.82}{32} \: or \: \: t = \frac{ - 21 - 121.82}{32} \\ t = 3.15 \: \: or \: \: t = - 4.46[/tex]
time cannot be negative, hence t = -4.46 can be avoided
The ball takes 3.15 seconds to hit the ground.