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jarptica [38.1K]

3 years ago

13

Brian drove 120 miles at a speed of 60 mph. He drove the same distance back home at an average speed of 40 mph. Brian adds the s

peeds and divides by two to come up with an average speed of 50 mph what is wrong with his reasoning? Find his average speed

1 answer:

Helen [10]3 years ago

4 0

This is how to find the average speed: the total distance ÷ the total number of hours
the total distance in this case is 120+120=240
the total hours is 120/60 + 120/40 =2+3=5
so 240/5=48
48 miles per hour

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Y=6.75x
He charges $6.75 per hour

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2 years ago

What’s the answer to this

dangina [55]

Answer:

c

Step-by-step explanation:

y is equal to 6 multiplied by IxI

for example, if x was 1 the coordinates would be (1,6).

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3 years ago

Solve and show your work for each question a). B). C).

Andreyy89

Answer:

Step-by-step explanation:

a) Here, the first term is .48 and the common ratio is 1/100 (since each new 48 is 1/100 th of the previous 48). a

Use the formula s = sum of geometric series = -----------

1 - r

0.48 48

which in this case is s = --------------- = ------------ = 48/99 = 16/33

1 - 1/100 100 - 1

Check this result by finding 16/33 on a calculator. Is the result equal to 0.484848484848.... ? Yes

b) Here we have the bar over the 8 only. 0.48 with the bar over the 8 is equivalent to 0.4888888888 ...

0.08

or 0.4 + 0.0888888888 ... or 0.4 + ------------

1 - 1/10

0.08 8

and this simplifies to 0.4 + ------------ = 0.4 + ---------

9/10 90

Evaluating this last result on a calculator results in 0.488888888 ...

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3 years ago

How do you estimate 10.43

Veronika [31]

Answer:

Step-by-step explanation:

Given 10.43, you can 'estimate' it only by rounding off:

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3 years ago

Two shooters, Rodney and Philip, practice at a shooting range. They fire rounds each at separate targets. The targets are mark

Sedaia [141]

Complete Question

Answer:

a

$SE = 0.66}$

b

$-3.29 < \mu_1 - \mu_2 < -0.70$

Step-by-step explanation:

From the question we are told that

The sample size is n = 60

The first sample mean is $\= x _1 = 8$

The second sample mean is $\= x _2 = 10$

The first variance is $v_1 = 0.25$

The first variance is $v_2 = 0.55$

Given that the confidence level is 95% then the level of significance is 5% = 0.05

Generally from the normal distribution table the critical value of $\frac{\alpha }{2}$ is

$Z_{\frac{\alpha }{2} } = 1.96$

Generally the first standard deviation is

$\sigma_1 = \sqrt{v_1}$

=> $\sigma_1 = \sqrt{0.25}$

=> $\sigma_1 = 0.5$

Generally the second standard deviation is

$\sigma_2 = \sqrt{v_2}$

=> $\sigma_2 = \sqrt{0.55}$

=> $\sigma_2 = 0.742$

Generally the first standard error is

$SE_1 = \frac{\sigma_1}{\sqrt{n} }$

$SE_1 = \frac{0.5}{\sqrt{60} }$

$SE_1 = 0.06$

Generally the second standard error is

$SE_2 = \frac{\sigma_2}{\sqrt{n} }$

$SE_2 = \frac{0.742}{\sqrt{60} }$

$SE_2 = 0.09$

Generally the standard error of the difference between their mean scores is mathematically represented as

$SE = \sqrt{SE_1^2 + SE_2^2 }$

=> $SE = \sqrt{0.06^2 +0.09^2 }$

=> $SE = 0.66}$

Generally 95% confidence interval is mathematically represented as

$(\= x_1 -\= x_2) -(Z_{\frac{\alpha }{2} } * SE) < \mu_1 - \mu_2 < (\= x_1 -\= x_2) +(Z_{\frac{\alpha }{2} } * SE)$

=> $(8 -10) -(1.96 * 0.66) < \mu_1 - \mu_2 < (8-10) +(Z_{\frac{\alpha }{2} } * 0.66)$

=> $-3.29 < \mu_1 - \mu_2 < -0.70$

5 0

4 years ago