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.
Suppose a tank contains 400 gallons of salt water. If pure water flows into the tank at the rate of 7 gallons per minute and the mixture flows out at the rate of 3 gallons per minute, how many pounds of salt will remain in the tank after 16 minutes if 28 pounds of salt are in the mixture initially? (Give your answer correct to at least three decimal places.)
Answer:
Step-by-step explanation:
This is a differential equation problem most easily solved with an exponential decay equation of the form
[tex]y=Ce^{kt}[/tex]. We know that the initial amount of salt in the tank is 28 pounds, so
C = 28. Now we just need to find k.
The concentration of salt changes as the pure water flows in and the salt water flows out. So the change in concentration, where y is the concentration of salt in the tank, is [tex]\frac{dy}{dt}[/tex]. Thus, the change in the concentration of salt is found in
[tex]\frac{dy}{dt}=[/tex] inflow of salt - outflow of salt
Pure water, what is flowing into the tank, has no salt in it at all; and since we don't know how much salt is leaving (our unknown, basically), the outflow at 3 gal/min is 3 times the amount of salt leaving out of the 400 gallons of salt water at time t:
[tex]3(\frac{y}{400})[/tex]
Therefore,
[tex]\frac{dy}{dt}=0-3(\frac{y}{400})[/tex] or just
[tex]\frac{dy}{dt}=-\frac{3y}{400}[/tex] and in terms of time,
[tex]-\frac{3t}{400}[/tex]
Thus, our equation is
[tex]y=28e^{-\frac{3t}{400}[/tex] and filling in 16 for the number of minutes in t:
y = 24.834 pounds of salt
6. Lerato wants to purchase a house
that costs R 850 000. She is required to
pay a 12% deposit and she will borrow
the balance from a bank. Calculate
the amount that Lerato must borrow
from the bank.
Answer:
J
Step-by-step explanation:
Answer: 748,000
Step-by-step explanation: Multiply 850,000 by 0.12 and you would get 102,000 then you would subract 102,000 from 850,000 getting 748,000
A decorative wall in a garden is to be built using bricks that are 5 1/2 inches thick and mortar joints are 1/4 inch thick. What is the height of the wall?
Step-by-step explanation:
SAVE
HOME HACKS & ANSWERSBUILDING & REMODELINGWALLS
How to Calculate How Many Bricks to Build a Wall
By KELVIN O'DONAHUE
Hunker may earn compensation through affiliate links in this story.
...
To estimate the number of bricks needed to build a wall, first measure a single brick.
A wall built from brick not only adds security and strength to your property, it also provides a pleasing geometric backdrop for the landscaping. Because of the bricks' size and weight, homeowners generally arrange to have the amount needed for a large project delivered by the masonry company or lumberyard. Doing so requires that you estimate the number of bricks needed before placing the order.
Step 1
Measure the length and thickness of one of the bricks that will be used in the wall. A standard brick is 2-1/4 inches wide and 7-1/2 to 8 inches long. Add 1/2 inch to both the length and thickness to account for the mortar joint between adjacent bricks. For example, a brick that is 2-1/4 inches by 7-1/2 inches, plus mortar joints, will occupy 2 3/4 inches by 8 inches.
Step 2
Measure the length of the space for the wall and convert the number to inches. Divide the length in inches by the length of a brick plus mortar joint. For example, a wall 36 feet, 8 inches long is 440 inches long (36 X 12 = 432 + 8 = 440). Each course (single layer) of bricks will need 440 / 8 = 55 bricks.
SAVE
HOME HACKS & ANSWERSBUILDING & REMODELINGWALLS
How to Calculate How Many Bricks to Build a Wall
By KELVIN O'DONAHUE
Hunker may earn compensation through affiliate links in this story.
...
To estimate the number of bricks needed to build a wall, first measure a single brick.
A wall built from brick not only adds security and strength to your property, it also provides a pleasing geometric backdrop for the landscaping. Because of the bricks' size and weight, homeowners generally arrange to have the amount needed for a large project delivered by the masonry company or lumberyard. Doing so requires that you estimate the number of bricks needed before placing the orderStep 3
Determine the desired height of the wall in inches, and divide the height by the thickness of a brick and mortar joint. For example, a wall 72 inches tall requires 26.18 courses of 2-3/4-inch-wide bricks; rounded up to 27 courses.
Step 4
Multiply the number of bricks per course (55) by the number of courses (27) to obtain the number of bricks in a single-thickness wall or veneer. For our example, the number is 1,485 bricks. Double that number for a double-thickness wall. Bricklayers generally add 5 percent to the estimate to cover broken or wasted bricks, for about 1,560 bricks in this case
the old building at the back of the school is badly in need of repair. the company Hsa and the executive are planning to renovate the building to accommodate a new music room. There are 15 rooms in the building and the dimension of the rooms to be redone with tiles are 6m long and 4 m wide. ted the tile man has 500 one meter square tiles.
Explain how you would estimate whether Ted has enough tiles to cover all the kitchen floors in the entire apartment building?
How many tiles, each measuring 1 square meter, are needed to cover one room floor?
How many tiles are needed to cover all the floors in the entire building? Show your work?
Answer:
a. If the area of the tiles is greater than or equal to the area of all the rooms.
b. 24
c. 360
Step-by-step explanation:
a. Explain how you would estimate whether Ted has enough tiles to cover all the kitchen floors in the entire apartment building?
Ted would have enough tiles if the area of the tiles is greater than or equal to the area of all the rooms. Since we have 500 one meter square tiles, we have 500 m² of tiles.
Since the rooms are 6 m long and 4 m wide, the area of each room is 6 m × 4 m = 24 m². Since there are 15 rooms, the area of all the rooms is 15 × 24 m² = 360 m².
Since the area of the tiles = 500 m² is greater than the area of the rooms = 360 m², Ted would have enough tiles to cover all kitchen floors in the entire apartment building.
b. How many tiles, each measuring 1 square meter, are needed to cover one room floor?
Since the area of each room floor is 24 m² and the area of each tile is 1 m², so the number of 1 square meter tiles needed to cover each floor is n = area of floor/area of tile = 24 m²/1 m² = 24.
c. How many tiles are needed to cover all the floors in the entire building?
Since 24 tiles are needed to cover each floor and there are 15 rooms in the building, we would require 24 tiles/room × 15 rooms/building = 360 tiles.
So we require 360 tiles.
what is the quotient?
Answer:
the result gaven by dividing one number by another
Give an example of a function with both a removable and a non-removable discontinuity.
Answer:
(x+5)(x-3) / (x+5)(x+1)
Step-by-step explanation:
A removeable discontinuity is always found in the denominator of a rational function and is one that can be reduced away with an identical term in the numerator. It is still, however, a problem because it causes the denominator to equal 0 if filled in with the necessary value of x. In my function above, the terms (x + 5) in the numerator and denominator can cancel each other out, leaving a hole in your graph at -5 since x doesn't exist at -5, but the x + 1 doesn't have anything to cancel out with, so this will present as a vertical asymptote in your graph at x = -1, a nonremoveable discontinuity.
The average undergraduate cost for tuition, fees, and room and board for two-year institutions last year was $13,252. The following year, a random sample of 20 two-year institutions had a mean of $15,560 and a standard deviation of $3500. Is there sufficient evidence at the ?= 0.05 level to conclude that the mean cost has increased. Solve the question by traditional approach.
Answer:
The p-value of the test is 0.0041 < 0.05, which means that there is sufficient evidence at the 0.05 significance level to conclude that the mean cost has increased.
Step-by-step explanation:
The average undergraduate cost for tuition, fees, and room and board for two-year institutions last year was $13,252. Test if the mean cost has increased.
At the null hypothesis, we test if the mean cost is still the same, that is:
[tex]H_0: \mu = 13252[/tex]
At the alternative hypothesis, we test if the mean cost has increased, that is:
[tex]H_1: \mu > 13252[/tex]
The test statistic is:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question
[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, s is the standard deviation and n is the size of the sample.
13252 is tested at the null hypothesis:
This means that [tex]\mu = 13252[/tex]
The following year, a random sample of 20 two-year institutions had a mean of $15,560 and a standard deviation of $3500.
This means that [tex]n = 20, X = 15560, s = 3500[/tex]
Value of the test statistic:
[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]
[tex]t = \frac{15560 - 13252}{\frac{3500}{\sqrt{20}}}[/tex]
[tex]t = 2.95[/tex]
P-value of the test and decision:
The p-value of the test is found using a t-score calculator, with a right-tailed test, with 20-1 = 19 degrees of freedom and t = 2.95. Thus, the p-value of the test is 0.0041.
The p-value of the test is 0.0041 < 0.05, which means that there is sufficient evidence at the 0.05 significance level to conclude that the mean cost has increased.
On Monday, 27 adults visited an amusement park. On Tuesday, 23 adults visited the amusement park. The enterance fee for the adults is Rs. 100. How much amount is collected from the adults in these two days?
PLEASE TELL FULL SOLUTION.
Answer:
5000
Step-by-step explanation:
Add the number of adults first: 27+23=50
Then multiply the number of adults by 100 for the fee.
50*100 = 5000
Answer:
within the two days a total of 5000$ where collected in the two days
Solution:
R= 100 per adult
1 adult = 100
27(R)+ 23(R) = 27(100)+ 23(100)
27(100)+23(100) =5000
or add both 27 and 23 and multiple by 100
50•100 = 5000
if an angle is bisected to form two new 20 degree angles, what was the measure of the original angle?
Answer:
10 degrees
Step-by-step explanation:
The angle bisected so that mean it was divided into 2 parts, so if it's 20 degree angles bisected it's divided by 2:
20/2= 10°
So the measure of the original angle is 10° degrees!
Answer:40
Step-by-step explanation: i took the lesson this was the answer
3. Of 1000 randomly selected cases of lung cancer, 450 resulted in death within 5 years. Calculate a 96% CI on the death rate from lung cancer.
Answer:
The 96% CI on the death rate from lung cancer is (0.4177, 0.4823).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.
[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
Of 1000 randomly selected cases of lung cancer, 450 resulted in death within 5 years.
This means that [tex]n = 1000, \pi = \frac{450}{1000} = 0.45[/tex]
96% confidence level
So [tex]\alpha = 0.04[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.04}{2} = 0.98[/tex], so [tex]Z = 2.054[/tex].
The lower limit of this interval is:
[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.45 - 2.054\sqrt{\frac{0.45*0.55}{1000}} = 0.4177[/tex]
The upper limit of this interval is:
[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.45 + 2.054\sqrt{\frac{0.45*0.55}{1000}} = 0.4823[/tex]
The 96% CI on the death rate from lung cancer is (0.4177, 0.4823).
Which sequence is geometric?
O 1,5, 9, 13, ….
O 2, 6, 8, 10, ...
O 5, 7, 9, 11, ....
O 4, 8, 16, 32, ….
Answer:
4, 8, 16, 32, ...
Step-by-step explanation:
8 / 4 = 2
16 / 8 = 2
32 / 16 = 2
Common ratio is 2
So, The sequence 4, 8, 16, 32, …. is geometric.
The mean number of words per minute (WPM) typed by a speed typist is 149 with a standard deviation of 14 WPM. What is the probability that the sample mean would be greater than 147.8 WPM if 88 speed typists are randomly selected
Answer:
78.81%
Step-by-step explanation:
We are given;
Population mean; μ = 149
Sample mean; x¯ = 147.8
Sample size; n = 88
standard deviation; σ = 14
Z-score is;
z = (x¯ - μ)/(σ/√n)
Plugging in the relevant values;
z = (147.8 - 149)/(14/√88)
z = -0.804
From z-distribution table attached, we have; p = 0.21186
P(X > 147.8) = 1 - 0.21186 = 0.78814
In percentage gives; p = 78.81%
anyone have sna pc hat ??
mine is rince9253
Answer:
Yeah the answer is n o .
Answer:
yes i do have but i dont use it
PLEASE I NEED SO MUCH HELP HERE!!!!!!
There are twelve shirts in my closet. Five are red, four are blue, and three are green. What is
the probability that I choose a red or blue shirt to wear tomorrow?
O 65%
0 75%
0 80%
60%
58%
Answer:
the probability that I chose red or blue is 75%
75%
DE is tangent to Circle C at point D.
What is the measure of
Enter your answer in the box.
Answer:
39°
Step-by-step explanation:
A radius of a circle (segment CD) drawn to the point of tangency (D) intersects the tangent (line DE) at a 90-deg angle.
That makes m<D = 90.
m<D + m<C + m<E = 180
90 + 51 + m<E = 180
m<E = 39
Peter is 8 years younger than Alex. In 9 years time, the sum of their ages will be 76 . How old is Alex now?
Answer:
Peter is a-8 in 9 years, (a-8)+ 9+ a+ 9= 76
Answer:
P = 25
A = 33
Step-by-step explanation:
P + 8 = A
P + 9 + A + 9 = 76
P + A = 58
~~~~~~~~~~~~~~
P = 58 - A
P = 58 - P - 8
2 P = 50
P = 25
A = 33
Determine how much interest you would earn on the following investment:
$190,000 invested at a 6.9% interest rate for 9 months.
2. What facts are needed to solve the problem?
Answer:
firstly we have to identify the problems, understand carefully and chose the best way to solve problems.
If f(x) =4x2 - 8x - 20 and g(x) = 2x + a, find the value of a so that the y-intercept of the graph of the composite function (fog)(x) is (0, 25).
Answer:
The possible values are a = -2.5 or a = 4.5.
Step-by-step explanation:
Composite function:
The composite function of f(x) and g(x) is given by:
[tex](f \circ g)(x) = f(g(x))[/tex]
In this case:
[tex]f(x) = 4x^2 - 8x - 20[/tex]
[tex]g(x) = 2x + a[/tex]
So
[tex](f \circ g)(x) = f(g(x)) = f(2x + a) = 4(2x + a)^2 - 8(2x + a) - 20 = 4(4x^2 + 4ax + a^2) - 16x - 8a - 20 = 16x^2 + 16ax + 4a^2 - 16x - 8a - 20 = 16x^2 +(16a-16)x + 4a^2 - 8a - 20[/tex]
Value of a so that the y-intercept of the graph of the composite function (fog)(x) is (0, 25).
This means that when [tex]x = 0, f(g(x)) = 25[/tex]. So
[tex]4a^2 - 8a - 20 = 25[/tex]
[tex]4a^2 - 8a - 45 = 0[/tex]
Solving a quadratic equation, by Bhaskara:
[tex]\Delta = (-8)^2 - 4(4)(-45) = 784[/tex]
[tex]x_{1} = \frac{-(-8) + \sqrt{784}}{2*(4)} = \frac{36}{8} = 4.5[/tex]
[tex]x_{2} = \frac{-(-8) - \sqrt{784}}{2*(4)} = -\frac{20}{8} = -2.5[/tex]
The possible values are a = -2.5 or a = 4.5.
F(x) =-2x-4 find x if f(x)=14
Answer:
14=-2x-4
18=-2x
x=-9
Hope This Helps!!!
Which of the following best describes the relationship between angle a and angle bin the image below?
On Monday, Ray had $153.75 in his bank account. On Tuesday, he withdrew $71.00 from his account. After depositing #292.50 on Wednesday, how much money did Ray have in his account
Answer:
$375.25
Step-by-step explanation:
[tex]===========================================[/tex]
Withdrew- taking out money (-)
Deposit- putting in money (+)
[tex]===========================================[/tex]
Ray started off with 153.75. He withdraws (-) 71.
[tex]153.75-71=82.75[/tex]
Then he deposits (+) 292.5.
[tex]82.75+292.5=375.25[/tex]
That's your answer!
I hope this helps ❤
If U= {1,2,3,......8} , A={1,4,6,7} , B= {2,4,5,7} & C= {3,5,6,7} prove that 1) An( BUC ) = ( AnB) U ( AnC ). 2) AU (BnC)= (AUB) n ( AUC )
Step-by-step explanation:
BUC={2,3,4,5,6,7}
An(BUC)={4,6,7}
AnB={4,7},AnC={6,7}
(AnB)U(AnC)={4,6,7}
Au(BnC)={1,4,5,6,7}
(AUB)n(AUC)= {1,4,5,6,7}
OMG THIS IS SO HARD
Answer:
Answer to the first question is D. Answer to the second question is also D.
Step-by-step explanation:
First question:
All the sides of the square are equal meaning you just have to multiply 1 side by 4 to get the perimeter(all the sides added together.) If one side is (s+3) then you either add that to itself 4 times or multiply it by 4. It's the same thing so it's 4(s+3) and (s+3)+(s+3)+(s+3)+(s+3).
Second question:
Adding a negative number is equivalent to subtracting a positive number. In this case, 59.2-84.7 = 59.2+(-84.7)
Given the following numbers: a = 12500000 b = 0.00125 c = 1120000
Calculate (ab)÷ (c) and write the answer in standard form. (2.5 marks)
d) Express the interval (-1.5, 4] as an inequality and then graph the interval.
Answer:
Answer to the following question is as follows.
Step-by-step explanation:
Given:
a = 12500000
b = 0.00125
c = 1120000
Calculate (ab) ÷ (c)
Given:
d) Express the interval [-1.5, 4] as an inequality and then graph
Computation:
(ab) ÷ (c) = (a)(b) / c
(ab) ÷ (c) = (12500000)(0.00125) / (1120000)
(ab) ÷ (c) = 25 / 1,792
Express the interval [-1.5, 4]
{x : -1.5 < x ≤ 4}
Graph.
._________._________.
-1.5 0 4
what’s the answer to this problem please and thank you
Answer:
1.8574 hours
Step-by-step explanation:
Solve for t.
Take the natural log of both sides.
[tex] 3000 = 75000e^{-1.733t} [/tex]
[tex] 1 = 25e^{-1.733t} [/tex]
[tex] \dfrac{1}{25} = e^{-1.733t} [/tex]
[tex] \ln \dfrac{1}{25} = \ln (e^{-1.733t}) [/tex]
[tex] -3.218875 = -1.733t [/tex]
[tex] t = 1.8574[/tex]
6. Two cell phone companies charge a flat fee plus an added cost for each minute or part of a minute used. The cost is represented by C and the number of minutes is represented by t.
Call-More: C = 0.40t + 25 Talk-Now: C = 0.15t + 40
a) Which company is cheaper if a customer talks for 50 minutes. (1 mark)
b) Under what conditions do the two companies charge the same? (3 marks)
c) Under what conditions is Talk-Now better? Explain
Answer:
Call More is cheaper at 50 minutes
The two companies would charge the same for 60 minutes of use.
Talk Now is cheaper the more minutes you talk. At some point the rate of change of Call More makes it more expensive. That point is just after their costs are even.
Step-by-step explanation:
1. Which of the following ARE integers? (choose ALL that are integers
a. 35%,
b.-10,
c. 34,
d. 0.25,
e. 3105.
2. Which integer is between -3 and 4? (choose ONE answer)
a. 10
b. 3.14
c. O
Answer:
(1) -10, 34 and 3105
(2) 0
Step-by-step explanation:
Solving (a): Select all integers
The integers are numbers without decimal.
So, we have: -10, 34 and 3105
Other options are not integers
Solving (b): Select all integers between -3 and 4
Using the same explanation in (1) but with the range of -3 and 4. the integer is 0.
Other options are not integers
Match the pairs of equivalent exMatch the pairs of equivalent expressions.
pressions.
Answer:
Give us the picture or numbers please.
Step-by-step explanation:
Answer: add pic pls
Step-by-step explanation:
