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Lapatulllka [165]

3 years ago

6

Gabrielle drives her car 300 miles and averages a certain speed if the average speed has been 7 mph less she could have traveled

only 230 miles in the same length time what is the average speed

1 answer:

WARRIOR [948]3 years ago

8 0

Answer:

The average speed is 30 mph.

Step-by-step explanation:

The rate of change of distance with time is speed.

i.e Speed = $\frac{distance}{time}$

Let his average speed be represented by s.

Given that she covers 300 miles with an average speed.

So that;

s = $\frac{300}{t}$

⇒ t = $\frac{300}{s}$ .................. 1

Also, if her average speed has been 7 mph less, she could have traveled only 230 miles in the same length of time. This implies that;

(s - 7) = $\frac{230}{t}$

⇒ t = $\frac{230}{(s-7)}$ ............... 2

Thus equating 1 and 2, we have;

$\frac{300}{s}$ = $\frac{230}{(s-7)}$

230s = 300s - 2100

collecting like terms,

2100 = 300s - 230s

2100 = 70s

divide both sides by 70,

s = $\frac{2100}{70}$

= 30 mph

The average speed is 30 mph.

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Select the statement that correctly describes the expression below

Kitty [74]

Answer:

B

Step-by-step explanation:

The equation is (2x+5)^2.

It can't be A because 2 is the multiplier for only x.

It can't be C because the square is outside of the equation.

It can't be D because again, the square is outside of the equation.

So the only thing left is B.

Hope this helped!

7 0

3 years ago

Find the slope of the line that passes through (6, 7) and (2, 10). and simplify if needed thx guys.

tekilochka [14]

Answer:

$-\frac{3}{4}$

Step-by-step explanation:

the equation for finding the slope of a line when given two points is $\frac{y_2-y_1}{x_2-x_1}$ , aka the change in y over the change in x.

pick one of your coordinate pairs to be $y_2\\$ and $x_2$ . it doesn't matter which coordinate pair you choose as long as you keep them as $y_2\\$ and $x_2$ . the remaining coordinate pair will be $y_1$ and $x_1$ .

for this example, i'll use (2, 10) for $y_2\\$ and $x_2$ and (6, 7) for $y_1$ and $x_1$ .

<em>**before i begin, i just want to note that you can do these next four steps in any order that you want. i personally prefer to plug in my y-values first and then my x-values, but you can choose to instead plug in the values of each coordinate pair (like starting by plugging in the coordinate pair (2, 10) with 10 for </em> $y_2\\$ and 2 for $x_2$ <em>). it's up to you. i'm going to explain the steps by plugging in my y-values first and then my x-values because that's the way i normally do it.</em>

<em />

first, start by plugging in the y-value from the coordinate pair of your choosing in for $y_2\\$ . since i chose (2, 10) for $y_2\\$ and $x_2$ , i'll plug in 10 for $y_2\\$ .

$\frac{y_2-y_1}{x_2-x_1}$ ⇒ $\frac{10-y_1}{x_2-x_1}$

then plug in the remaining coordinate pair's y-value in for $y_1$ . since the coordinate pair that's left is (6, 7), i will plug in 7 for $y_1$ .

$\frac{y_2-y_1}{x_2-x_1}$ ⇒ $\frac{10-7}{x_2-x_1}$

now i'm going to plug in the x-values. i chose (2, 10) to plug in for $y_2\\$ and $x_2$ , so now i'll plug in 2 for $x_2$ .

$\frac{y_2-y_1}{x_2-x_1}$ ⇒ $\frac{10-7}{2-x_1}$

and all that's left to plug in is the x-value from (6, 7), so i will plug that in for $x_1$ .

$\frac{y_2-y_1}{x_2-x_1}$ ⇒ $\frac{10-7}{2-6}$

after plugging in all the values, you have $\frac{10-7}{2-6}$ .

subtract 10 - 7 as well as 2 - 6.

$\frac{10-7}{2-6}$ ⇒ $\frac{3}{-4}$

$\frac{3}{-4}$ cannot be simplified, therefore the slope of the line is $\frac{3}{-4}$ or $-\frac{3}{4}$ .

i hope this helps! have a lovely day <3

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2 years ago

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lorasvet [3.4K]

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3 0

3 years ago

An automobile manufacturer has given its van a 31.3 miles/gallon (MPG) rating. An independent testing firm has been contracted t

Fynjy0 [20]

Answer:

$z=\frac{31.1-31.3}{\frac{1.3}{\sqrt{140}}}=-1.82$

The p value for this case would be given by:

$p_v =2*P(z$

For this case since the p value is higher than the significance level we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true mean is not significantly different from 31.3 MPG

Step-by-step explanation:

Information given

$\bar X=31.1$ represent the sample mean

$\sigma=1.3$ represent the population standard deviation

$n=140$ sample size

$\mu_o =31.3$ represent the value that we want to test

$\alpha=0.02$ represent the significance level for the hypothesis test.

z would represent the statistic

$p_v$ represent the p value

Hypothesis to test

We want to test if the true mean is equal to 31.3 MPG, the system of hypothesis would be:

Null hypothesis: $\mu =31.3$

Alternative hypothesis: $\mu \neq 31.3$

Since we know the population deviation, the statistic is given by

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

Replacing we got:

$z=\frac{31.1-31.3}{\frac{1.3}{\sqrt{140}}}=-1.82$

The p value for this case would be given by:

$p_v =2*P(z$

For this case since the p value is higher than the significance level we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true mean is not significantly different from 31.3 MPG

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3 years ago

3. A farm has 40m of fence. What is the maximum area he can

Nataliya [291]

Answer:

160m squared

Step-by-step explanation:

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3 years ago