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Margaret [11]
3 years ago
9

A family has two cars. The first car has a fuel efficiency of 20 miles per gallon of gas and the second has a fuel efficiency of

15 miles per gallon of gas. During
one particular week, the two cars went a combined total of 1325 miles, for a total gas consumption of 75 gallons. How many gallons were consumed by each of
the two cars that week?
Mathematics
1 answer:
kogti [31]3 years ago
6 0

Answer:

40 and 35

Step-by-step explanation:

If we say the first car uses x gallons then the second car must use 75 - x gallons.

The distance travelled is the number of gallons used * the efficiency of the car.

20x + 15(75-x)=1325

20x + 1125 - 15x = 1325

5x = 200

x = 40

This means that the first car uses 40 gallons and the second car uses 75-40= 35 gallons

You might be interested in
Explain two methods for solving an equation. Give an example.
svlad2 [7]

For solving system of equations, we can use either substitution where we plug one equation into the other, or elimination where we combine the equations.


- Using elimination, you would to eliminate one variable from both equations, so you automatically would get one equation with one variable!


- Using substitution means you are going to solve one equation for one variable and substitute with its value in the other equation in order to get also an equation with one variable.



Let's take an example ...

y+x=2            and      y-2x = 1

<span>Using <span>elimination, we need to subtract these two equation; one from the other...

y+x=2
-
y-2x=1
-----------
0+3x=1

then x=1/3       

and then substitute into any equation to get y-value</span></span>
y+x=2
y+1/3 = 2        >>>>>    y=5/3



NOW...<span>Using substitution
</span>y+x=2            and      y-2x = 1 >>(y=1+2x)

Plug (y=1+2x) into y+x=2    and solve for x
y+x=2
(1+2x) + x =2
1+3x = 2
3x=1

again (and for sure) x = 1/3

plug in x=1/3 into any of the equations above to get y:
y+x=2
y+1/3=2
y=5/3


DOne  !!!!!!


I hope you got the idea

If you still need help, just let me know.




7 0
3 years ago
Please help, ty if you do :D
Dennis_Churaev [7]

Answer:

Your Answer is going to be C

3 0
2 years ago
"A cable TV company wants to estimate the percentage of cable boxes in use during an evening hour. An approximation is 20 percen
Marizza181 [45]

Answer:

The company should take a sample of 148 boxes.

Step-by-step explanation:

Hello!

The cable TV company whats to know what sample size to take to estimate the proportion/percentage of cable boxes in use during an evening hour.

They estimated a "pilot" proportion of p'=0.20

And using a 90% confidence level the CI should have a margin of error of 2% (0.02).

The CI for the population proportion is made using an approximation of the standard normal distribution, and its structure is "point estimation" ± "margin of error"

[p' ± Z_{1-\alpha /2} * \sqrt{\frac{p'(1-p')}{n} }]

Where

p' is the sample proportion/point estimator of the population proportion

Z_{1-\alpha /2} * \sqrt{\frac{p'(1-p')}{n} } is the margin of error (d) of the confidence interval.

Z_{1-\alpha /2} = Z_{1-0.05} = Z_{0.95}= 1.648

So

d= Z_{1-\alpha /2} * \sqrt{\frac{p'(1-p')}{n} }

d *Z_{1-\alpha /2}= \sqrt{\frac{p'(1-p')}{n} }

(d*Z_{1-\alpha /2})^2= \frac{p'(1-p')}{n}

n*(d*Z_{1-\alpha /2})^2= p'(1-p')

n= \frac{p'(1-p')}{(d*Z_{1-\alpha /2})^2}

n= \frac{0.2(1-0.2)}{(0.02*1.648)^2}

n= 147.28 ≅ 148 boxes.

I hope it helps!

3 0
3 years ago
Work out the size of angle x <br> Next to 164 and 90
Zielflug [23.3K]

Answer:

x=106 degrees

Step-by-step explanation:

I'm going to assume that this is a circle since you didn't give it to me

So you want to add 164 and 90 together and subtract the sum by 360

360-(164+90)=106

So you want to use PEMDAS (order of operations) to solve this

  1. so do what's in the perenthesis first so 164+90=254
  2. Then you want to subtract 254 from 360 so 360-254=106

x=106 degrees

6 0
2 years ago
What is 3/15 times 3/8 in fraction form?
bekas [8.4K]

Answer:

9/40

Step-by-step explanation:

3/5 * 3/8 = 9/40

5 0
3 years ago
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