Answer:
a) P(0) = 80
b) [tex]P(t) = 80(2.2361)^t[/tex]
c) 22,363 cells.
d) The rate of growth after 7 hours is of 18,000 bacteria per hour.
e) 9.7 hours.
Step-by-step explanation:
A bacteria culture grows with a constant relative growth rate.
This means that the population is given by:
[tex]P(t) = P(0)(1+r)^t[/tex]
In which P(0) is the initial population and r is the growth rate, as a decimal.
After 2 hours there are 400 bacteria and after 8 hours the count is 50,000.
This means that in 6 hours, the population went from 400 bacteria to 50,000 bacteria. We use this to find r. So
[tex]50000 = 400(1+r)^6[/tex]
[tex](1+r)^6 = \frac{50000}{400}[/tex]
[tex](1+r)^6 = 125[/tex]
[tex]\sqrt[6]{(1+r)^6} = \sqrt[6]{125}[/tex]
[tex]1 + r = 125^{\frac{1}{6}}[/tex]
[tex]1 + r = 2.2361[/tex]
So
[tex]P(t) = P(0)(2.2361)^t[/tex]
(a) Find the initial population. P(0)
We have that P(2) = 400. We use this to find P(0). So
[tex]P(t) = P(0)(2.2361)^t[/tex]
[tex]400 = P(0)(2.2361)^2[/tex]
[tex]P(0) = \frac{400}{(2.2361)^2}[/tex]
[tex]P(0) = 80[/tex]
So
[tex]P(t) = 80(2.2361)^t[/tex]
(b) Find an expression for the population after t hours.
[tex]P(t) = 80(2.2361)^t[/tex]
(c) Find the number of cells after 7 hours.
This is P(7). So
[tex]P(7) = 80(2.2361)^7 = 22363[/tex]
22,363 cells.
(d) Find the rate of growth after 7 hours.
We have to find the derivative when t = 7. So
[tex]P(t) = 80(2.2361)^t[/tex]
[tex]P^{\prime}(t) = 80\ln{2.2361}(2.2361)^t[/tex]
[tex]P^{\prime}(7) = 80\ln{2.2361}(2.2361)^7 = 18000[/tex]
The rate of growth after 7 hours is of 18,000 bacteria per hour.
(e) When will the population reach 200,000?
This is t for which [tex]P(t) = 200000[/tex]. So
[tex]P(t) = 80(2.2361)^t[/tex]
[tex]200000 = 80(2.2361)^t[/tex]
[tex](2.2361)^t = \frac{200000}{80}[/tex]
[tex](2.2361)^t = 2500[/tex]
[tex]\log{(2.2361)^t} = \log{2500}[/tex]
[tex]t\log{2.2361} = \log{2500}[/tex]
[tex]t = \frac{\log{2500}}{\log{2.2361}}[/tex]
[tex]t = 9.7[/tex]
So 9.7 hours.
A machining center is in charge of producing 225 parts per day. The parts width. Any parts produced between 250mm and 260mm are considered gless than 250mm must be reworked at an additional cost of $8 per part. 260mm must be reworked at an additional cost of $2.50 per part. The varquantified as a standard deviation of 5.0mm. Measurements on these parhave the ability to set up the machine to achieve whatever mean width value you wish.
Required:
Setup a data table to determine the mean width setting that will minimize expected rework cost ($8 per small part and $2.50 per large part).
When a closed curve is parameterized by {x[t], y[t]}, then as you advance along the curve in the direction of the parameterization, which way do the tangent vectors {x'[t], y'[t]} at {x[t], y[t]} point; in the direction you are going, or in the direction opposite to the direction you are going?
Answer:
In the direction you are going,
Explanation:
We know that the tangent to {x[t], y[t]} are {x'[t], y'[t]}. Since {x'[t], y'[t]} are tangents at {x[t], y[t]}, we know that the tangent at a point is always parallel to the direction of the function at that point and in the direction of the function. So, the tangent vectors {x'[t], y'[t]} at {x[t], y[t]} point in my direction of motion as I move along the curve.
So, the tangent vectors {x'[t], y'[t]} at {x[t], y[t]} point in the direction you are going.
An angle measures 19.4° more than the measure of its complementary angle. What is the measure of each angle?
Answer:
37.8+52.2=90
Step-by-step explanation: x + (x + 14.4) = 90
2x + 14.4 = 90
2x = 75.6
x = 37.8 (one angle)
And (x + 14.4) = 52.2 (other angle).
I don’t know the answer!!
I’m new to this app and I need help if you know the answer please tell me I don’t know English very good please help me.
Answer:
A. 2.04 seconds
B. 5.92
C: 1.48 - 0.4 = 1.08 seconds
Step-by-step explanation:
~~~~~~~~~~~~~~~~~~~~~
USE THIS TO GET "B"
the f(-b/2a) is the highest point,
the vertex of the parabola [-b/2a, f(-b/2a)] will give you the time
and height of the highest point
~~~~~~~~~~~~~~~~~~~
USE THIS TO GET "A"... you will get two answers one will be negative
ignore that one , the positive one is the time to hit the ground
if you factor the equation (use the quadratic formula) you will get
the "zeros" that is where the ball is on the ground...
~~~~~~~~~~~~~~~~~~~~~~~
THIS IS FOR PART "C"
if you set the equation equal to 4.5 meters and factor that for the "zeros" you will get the two times that the ball is at that height.. subtract the two times for the duration
9 3/5 % as a decimal, rounded to 3 decimal places, is:
If a number is divisible by 6 and 8 then is it also divisible by 48?
Answer:
No
Step-by-step explanation:
Let's look at an example
24
24 is divisible by 6 24/6 = 4
24 is divisible by 8 24/8 = 3
24 is not divisible by 48 24/48 = 1/2 which is not an integer
A tumor is injected with 0.3 grams of Iodine-125, which has a decay rate of 1.15% per day. To the nearest day, how long will it take for half of the Iodine-125 to decay?
Answer:
The time required is 60.3 days.
Step-by-step explanation:
initial amount, No = 0.3 g
rate, r = 1.15 % per day = 0.0115 per day
final amount, N = 0.15 g
Let the time is t.
[tex]N = No e^{-rt}\\\\0.15 = 0.3 e^{-0.0115 t}\\\\0.5 =e^{-0.0115 t}\\\\- 0.6931 = - 0.0115 t \\\\t = 60.3 days[/tex]
Question 1 of 10
If f(x)= 2 -3 and g(x) = 4x2 + x - 4, find (f+ g)(x).
O A. 4x+x-7
O B. 4x2 +5x-1
O c. 6x2 - 7
OD 6+x-1
A
SUBMIT
Answer:
I believe it's A
Step-by-step explanation:
I'm not sure sorry if its wrong
Zelina scored 10% higher on her second quiz than on her first quiz. On her third quiz, Zelina scored 20% higher than on her second quiz. Her third quiz score is what percent higher than her first quiz score?
Answer:
30%
Step-by-step explanation:
you just add 10% and 20%
Hope it helps c:
Zelina scored 32% higher on the third quiz than on her first quiz.
What is the percentage?The Percentage is defined as representing any number with respect to 100. It is denoted by the sign %.
Given that:-
Zelina scored 10% higher on her second quiz than on her first quiz. On her third quiz, Zelina scored 20% higher than on her second quiz.From the given data we will see that:-
1 ) Zelina scored 10% higher on her second quiz than on her first quiz.
SQ = 1.10 FQ
2 ) On her third quiz, Zelina scored 20% higher than on her second quiz
TQ = 1.20SQ
From the above to expression solve for the first quiz:-
TQ = 1.20 x 1.10 FQ
TQ = 1.32FQ
Therefore Zelina scored 32% higher on the third quiz than on her first quiz.
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Solve the system using substitution. x+y=-2 and x-y=-8
Answer:
1) x+y=-2
x=-2-y
2) x-y=-8
substitude value of x
(-2-y)-y=-8
-2-2y=-8
-2y=-6
y=3
Substitute value of y in 1
x=-2-3
x=-5
Brainliest please~
The numbers of home runs that Barry Bonds hit in the first 18 years of his major league baseball career are listed below. Find the mean and median number of home runs. Round the mean to the nearest whole number. Which measure of central tendency- the mean or the median- best represents the data? Explain your reasoning.
16 25 24 19 33 25 34 46 37
33 42 40 37 34 49 73 46 45
Answer:
Mean = 35.56
Median = 35.5
Step-by-step explanation:
Given the data:
16 25 24 19 33 25 34 46 37
33 42 40 37 34 49 73 46 45
Reordered data :
16, 19, 24, 25, 25, 33, 33, 34, 34, 37, 37, 40, 42, 45, 46, 46, 49, 73
The mean = ΣX / n
n = sample size ; ΣX = sum of values
The mean = 658 / 18
The mean = 36.56
The Median = 1/2(n+1)th term
1/2(18+1)th term = 1/2(19)th term = 9.5 term
Median = (9th + 10th) / 2 = (34 + 37) / 2 = 35.5
A sample of 34 observations is selected from a normal population. The sample mean is 15, and the population standard deviation is 3. Conduct the following test of hypothesis using the 0.10 significance level. H0: μ ≤ 14 H1: μ > 14
Required:
a. Compute the value of the test statistic.
b. What is the p-value?
Answer:
1.944 ;
0.026
Step-by-step explanation:
Given :
Sample size, n = 34
Sample mean, xbar = 15
Population standard deviation, σ = 3
The hypothesis :
H0: μ ≤ 14
H1: μ > 14
The test statistic :
Test statistic = (xbar - μ) ÷ (σ/√(n))
Test statistic = (15 - 14) ÷ (3/√(34))
Test statistic = 1 / 0.5144957
Test statistic, Z = 1.944
The Pvalue :
Using the Pvalue from test statistic value :
Pvalue(1.944) = 0.026
Pvalue < α ; Reject H0
Couldn’t figure this out help please
(B)
Step-by-step explanation:
Rewrite the equations into their standard forms. The first one can be rewritten as
[tex]10x - 12y = -5[/tex]
and the 2nd can be rewritten as
[tex]3x + 5y = -1[/tex]
Solving this system either by substitution or elimination, we get
[tex]x = -\dfrac{37}{86}\:\:\text{and}\:\:y= \dfrac{25}{86}[/tex]
If you add x + y, you'll get a negative number.
9514 1404 393
Answer:
B. x + y < 0
Step-by-step explanation:
The two equations can be cleared of fractions by multiplying by 15.
15(2/3(x +1) -4/5y) = 15(1/3)
10(x +1) -12y = 5
10x -12y = -5
and
15(2/5x +1/3(2y +1)) = 15(1/5)
6x +5(2y +1) = 3
6x +10y = -2
3x +5y = -1 . . . . . eliminate common factor of 2
__
You can find the solutions any way you like, but you can answer the question without doing that. The lines are not parallel, nor coincident, so there is exactly one solution. (choices C and D are incorrect)
If we can locate the solution relative to the line x + y = 0, we can tell if choice A or choice B is correct. A quick look at the intercepts of the equations tells us the solution cannot lie in quadrants 1 or 4. The negative y-intercept and shallow slope (-3/5) of the second equation tells us the solution must lie below the line x + y = 0. That means x+y < 0, choice B.
_____
In the attached graph, the line x+y=0 is dashed orange. Above that line, x+y>0; below that line, x+y<0. We see the intersection point of the red and blue lines is in the region where x+y < 0.
For standard form equation ax+by = c, the x- and y-intercepts are c/a and c/b, respectively, so are easy to find from that form. Knowing these makes it easy to make a sketch of the graph, locating the solution point relative to the line x+y = 0.
Translate the following sentence into an algebraic inequality:
The difference of twice a number, x, and eleven is, at most, the sum of twenty and a number, x.
Question 4 options:
A)
2x∕11 ≥ 20 – x
B)
9x ≥ 20 + x
C)
2x + 11 ≥ 20x
D)
2x – 11 ≤ 20 + x
Answer:
it have to be letter c
Step-by-step explanation:
this the only problem matches with the question
The inequality represent the given phrase is 2x-11≤20+x. Therefore, option D is the correct answer.
What are inequalities?Inequalities are the mathematical expressions in which both sides are not equal. In inequality, unlike in equations, we compare two values. The equal sign in between is replaced by less than (or less than or equal to), greater than (or greater than or equal to), or not equal to sign.
Given that, the difference of twice a number, x, and eleven is, at most, the sum of twenty and a number, x.
The difference of twice a number, x, and eleven is
2x-11
The sum of twenty and a number, x
20+x
So, inequality is 2x-11≤20+x
The inequality represent the given phrase is 2x-11≤20+x. Therefore, option D is the correct answer.
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The length of a rectangle is 2 cm longer than its width.
If the perimeter of the rectangle is 36 cm, find its area.
Answer:
80 cm^2
Step-by-step explanation:
Let the width of the rectangle equal x. This means the length is x + 2, as it is 2 cm longer than the width. The formula for perimeter is: P = 2l + 2w, and substitute in the values of the length, width, and perimeter:
P = 2l + 2w
36 = 2(x + 2) + 2(x)
36 = 2x + 4 + 2x
36 = 4x + 4
4x = 32
x = 8
x represents the width, so the width is 8 and the length is 10. Area is length times width, so the area is 8 x 10 or 80 cm^2.
Step-by-step explanation:
let x be the width
p=2l+2w
36=2(2)+2(x)
36=4+2x
36-4=2x
32/2=2x/2(simplify)
x=16
therefore the width is 16cm
area of the rectangle is l×w
=2×16
=32cm"
therefore the area is 32cm"
The lengths of the three sides of a triangle are 17, 18, and 19. Classify it as acute, obtuse, or right.
Answer:
acute
Step-by-step explanation:
That triangle is an obtuse triangle
There is a rack of 15 billiard balls. Balls numbered 1 through 8 are solid-colored. Balsa numbered 9 through 15 contain stripes. If one ball is selected at random, determine the odds for it being striped.
If one ball is selected at random, the odds for it being striped are 7 out of 15, or 7/15.
What do we know?
We know that there are 15 billiard balls.
We also know that balls numbered 1 through 8 are solid-colored, so we have 8 solid-colored balls.
And the other 7 balls are striped.
Now we want to find the probability for a randomly selected ball to be a striped ball.
Because all the balls have the same probability of being randomly selected, the probability of randomly selecting a striped ball is equal to the quotient between the number of striped balls (7) and the total number of balls (15).
Then we have:
P = 7/15 = 0.467
That quotient is also what is called the "odds"
So if one ball is selected at random, the odds for it being striped are 7 out of 15, or 7/15.
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Which best describes the relationship between the line that passes through the points (6, –1) and (11, 2) and the line that passes through the points (5, –7) and (8, –2)?
A. same line
B. neither perpendicular nor parallel
C. perpendicular
D. parallel
Answer:
Step-by-step explanation:
slope of line through (6,-1) and (11,2) = (-1 - 2)/(6 - 11) = 3/5
slope of line through (5,-7) and (8,-2) = (-7 - (-2))/(8 - 5) = -5/3
product of the slopes = -1, so the lines are perpendicular.
If\[\displaystyle\frac{\sqrt{600} + \sqrt{150} + 4\sqrt{54}}{6\sqrt{32} - 3\sqrt{50} - \sqrt{72}} = a\sqrt{b},\]where $a$ and $b$ are integers and $b$ is as small as possible, find $a+b.$
9514 1404 393
Answer:
12
Step-by-step explanation:
Apparently, you want the sum a+b when ...
[tex]\[\displaystyle\frac{\sqrt{600} + \sqrt{150} + 4\sqrt{54}}{6\sqrt{32} - 3\sqrt{50} - \sqrt{72}} = a\sqrt{b},\][/tex]
A calculator can show you the expression on the left evaluates to √243. In simplest terms, that is 9√3, so we have a=9, b=3 and ...
a+b = 9+3 = 12
Answer:
12
Step-by-step explanation:
It costs $7.45 for 2.5 pounds of round steak. What is the unit rate?
A.$9.95 per pound
B.$18.63 per pound
C.$2.50 per pound
D.$2.98 per pound
Answer:
D.
Step-by-step explanation:
Since the unit rate is in dollars per pound, we divide the cost (in dollars) by the weight (in pounds.)
($7.45)/(2.5 lb) = $2.98 per pound
Answer: D.
Compute how many 7-digit numbers can be made from the digits 1, 2, 3, 4, 5, 6, 7 if there is no repetition and the odd digits must appear in an unbroken sequence. (Examples: 3571264 or 2413576 or 2467531, etc., but not 7234615.)
Answer:
Number of 7-digit numbers that can be made from the digit is 576
Step-by-step explanation:
Given the data in the question;
digits ⇒ 1, 2, 3, 4, 5, 6, 7
Number of odd numbers in the given digits = 4
Number of even numbers in the given digits = 3
now, we take the odd digits as a single unit.
so, number of ways the odd digits can be arranged with the unit will be 4!.
Now, lets consider the unit of 4 odd digits with 3 even digits.
there are 4 units.
so the number of possible arrangements of these 4 units = 4!
hence, Number of 7-digit numbers that can be made from the digits will be;
⇒ Number of possible arrangements of 4 units × Number of ways in which the odd digits can be arranged within the unit.
⇒ 4! × 4!
⇒ 576
Therefore, Number of 7-digit numbers that can be made from the digit is 576
Tìm x không âm biết √x =3
Answer:
x=9
Step-by-step explanation:
[tex]\sqrt{x}[/tex]=3
[tex]\sqrt{x}[/tex]^2=3^2
x=9
find the value of X in each figure below
Answer:
168). C
169). C
170). C
Step-by-step explanation:
For the first angle, it is a right angle, so it measures 90 degrees.
x and 50 are complementary angles, meaning they add up to 90 degrees.
So, subtract 50 from 90 to get 40, which is equal to x.
45 and x are supplementary angles, meaning they add up to 180 degrees.
Subtract 45 from 180 to get 35 degrees, which is the measure of angle x.
All angles in a triangle add up to 180 degrees.
So, 70 + 56 = 126, 180 - 126 = 54.
Since the unknown angle is x - 5, 54 + 5 = 59, which the the measure of angle x - 5.
In the picture below, which lines are lines of symmetry for the figure?
A. 1 and 3
B. only 3
C. 2
D. 1, 2, and 3
A line of symmetry would separate a shape to make multiple shapes that are exactly the same.
The answer is C.2
classmate Date 8) Solve the word problems a) If 576 balls are arranged in equal number of rows and columns, find the numbers of rows.
Answer:
24
Step-by-step explanation:
The number of rows (x) should b equal to the number of columns (x).
x²=576
x=√576 taking the square root of the product
x=24
Marilyn is retiring and wants to set up a 25-year annuity with 140 000 of her savings . The annuity earns 7.7 compounded monthly How much will Marilyn receive every month ?
Answer:
marilyn isrestiring and wants to set up a 25-year annuity earns 7.
Since lim n→ infinity (.............) = ...........
Notice that
[tex]\dfrac{4n+1}{8n+2}=\dfrac{4n+1}{2(4n+1)}=\dfrac12[/tex]
So by the root test,
[tex]\displaystyle\lim_{n\to\infty}\sqrt[n]{\left|\left(\frac12\right)^{2n}\right|} = \frac14 < 1[/tex]
and so the series converges (absolutely).
If my saving x$ grows 10% every year how much will I have in:
1 year
2 year
5 year
Answer:
[tex]1.1x, 1.21x, 1.61051x[/tex]
Step-by-step explanation:
If you saving grows [tex]10 \%[/tex] every year, then your saving is [tex]1.1\\[/tex] times your saving from last year. Therefore, after one year, you will have [tex]1.1x\\[/tex], then after [tex]2[/tex] years, you will have [tex](1.1)^2 \cdot x=1.21x[/tex], then after [tex]5[/tex] years, you will have [tex](1.1)^5 \cdot x = 1.61051x[/tex].
Answer:
$1.1x, $1.21x, $1.61x
Step-by-step explanation:
The Science Club arranged a trip to Smithsonian. Only 2/3 of the members were able to attend, which left one seat empty on the 25-passenger bus. How many members does the Science Club have?
Answer:
36 members
Step-by-step explanation:
Let x = the number of science club members
There are 24 people on the bus (1 seat empty on the 25 seat bus)
2/3 of the club attended and that equals 24 people on the bus
2/3x = 24
Multiply each side by 3/2
3/2 * 2/3x = 24 * 3/2
x = 36
I need two examples of rounding to the thousandths place. SHOW ALL WORK!
Answer:
3.418
Step-by-step explanation:
3.4175
3.4178
u round if the number behind it is higher than 5
