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2 years ago

Find the difference.

Mathematics

1 answer:

densk [106]2 years ago

7 0

Answer:

B. 13m+8

Step-by-step explanation:

(20m+3)-(7m-5)

= 20m+3-7m+5

= 13m+8

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4. A sum of money is divided among Khairul, Michael and Ethan in the ratio 6:4:5. After Khairul

Advocard [28]

Answer:

Step-by-step explanation:

8 0

1 year ago

A sociologist wishes to estimate the average number of automobile thefts in a large city per day within 2 automobiles. He wishes

anzhelika [568]

Answer:

$n=(\frac{2.58(4.2)}{2})^2 =29.35 \approx 30$

So the answer for this case would be n=30 rounded up to the nearest integer

Step-by-step explanation:

Information given

$ME = 2$ the margin of error desired

$\sigma =4.2$ standard deviation from previous studies

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =2 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 99% of confidence interval now can be founded using the normal distribution. The significance level is $\alpha=0.01$ and the critical value would be $z_{\alpha/2}=2.58$ , replacing into formula (b) we got:

$n=(\frac{2.58(4.2)}{2})^2 =29.35 \approx 30$

So the answer for this case would be n=30 rounded up to the nearest integer

5 0

2 years ago

Charlotte’s weekly paycheck is based on the number of hours worked during the week and on the weekend. If she works 13 hours dur

Gelneren [198K]

I am setting the week hourly rate to x, and the weekend to y. Here is how the equation is set up:

13x + 14y = $250.90
15x + 8y = $204.70

This is a system of equations, and we can solve it by multiplying the top equation by 4, and the bottom equation by -7. Now it equals:

52x + 56y = $1003.60
-105x - 56y = -$1432.90

Now we add these two equations together to get:

-53x = -$429.30 --> 53x = $429.30 --> (divide both sides by 53) x = 8.10. This is how much she makes per hour on a week day.

Now we can plug in our answer for x to find y. I am going to use the first equation, but you could use either.

$105.30 + 14y = $250.90. Subtract $105.30 from both sides --> 14y = $145.60 divide by 14 --> y = $10.40

Now we know that she makes $8.10 per hour on the week days, and $10.40 per hour on the weekends. Subtracting 8.1 from 10.4, we figure out that she makes $2.30 more per hour on the weekends than week days.

7 0

2 years ago

Read 2 more answers

Mikayla is training for a half-marathon. At the beginning of her training, she is able to run 2 miles without stopping. Her goal

ivanzaharov [21]

Alright, lets get started.

At the beginning of her training, she is able to run 2 miles without stopping means 2 will be in the addition when we will write the equation for her running miles.

Her goal is to increase her distance by three quarters of a mile each week.

Means in first week, she will add the distance = $\frac{3}{4}$ miles