A number I more than -13

A car was at a red light. When it turned green, the car accelerated to 25 km/hr in 5 sec. Calculate the acceleration. Was the ca

irinina [24]

Answer:

It accelerated at 5 km/hr/s or the car was going 5 km/h faster each second.

The car was speeding up

Step-by-step explanation:

To find an estimated acceleration, you just take the speed it got to and divide it by the tie it took to get there

s/t = a <---- where s = speed t = time a = acceleration

We know it was speeding up because it was at a red light so it was stopped. Then when it turned green, then the car would have started moving

3 0

3 years ago

Identify a common factor (other than 1) of terms in the expression-7x+21. Factor the expression to generate an equivalent expres

pashok25 [27]

Answer:

common factor = -7, equivalent expression -7(x -3)

Step-by-step explanation:

both terms have the 7 or -7 in common, once you factor it, you get -7(x-3)

5 0

3 years ago

Find the Area ( PLEASE LEAVE EXPLANATION)

LenaWriter [7]

Answer:

28 ft²

Step-by-step explanation:

Hello There!

To solve for the area of an irregular shape we want to split the irregular shape into regular shapes

For this irregular shape we would split it into a square with a side length of 2ft and a rectangle with a length of 6ft and a width of 4ft ( width was found subtracting total height of irregular figure (6ft) from height of square (2ft) 6ft - 2ft = 4ft so the width would be 4ft)

now we can easily solve for the area of each individual shape

area of square -

the area of a square can simply be found by raising the side length to the power of 2

so

$a =2^2\\2^2=4\\a=4ft^2$

so we can conclude that the area of the square is 4ft^2

Now we want to find the area of the rectangle

the area of a rectangle is simply equal to the width times the length

so

$a=6*4\\6*4=24\\\\a=24ft^2$

so we can conclude that the area of the rectangle is 24ft^2

Finally we add the two areas together

24 + 4 = 28

thus meaning the area of the irregular figure is 28 ft²

7 0

3 years ago

Can someone plz help me 0.004 x = 0.4

just olya [345]

Answer:

0.0016

Step-by-step explanation:

0.004*0.4=0.0016

3 0

4 years ago

Sacramento County high school seniors have an average SAT score of 1,020. From a random sample of 144 Sacramento High School stu

kari74 [83]

Answer:

We need to conduct a hypothesis in order to check if the high school students are representative of the overall population (or if the true mean is 1020 or not), the system of hypothesis would be:

Null hypothesis: $\mu = 1020$

Alternative hypothesis: $\mu \neq 1020$

Step-by-step explanation:

Previous concepts and data given

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=1100$ represent the sample mean

$s=144$ represent the sample standard deviation

n=144 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the high school students are representative of the overall population (or if the true mean is 1020 or not), the system of hypothesis would be:

Null hypothesis: $\mu = 1020$

Alternative hypothesis: $\mu \neq 1020$

If we analyze the size for the sample is > 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{1100-1020}{\frac{144}{\sqrt{144}}}=6.67$

P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=144-1 =143$

Then since is a two sided test the p value would be:

$p_v =2*P(t_{144}>6.67)=2.59x10^{-10}$

Conclusion

If we compare the p value and a significance level for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the population mean is significant different from 1020 at 5% of significance.

6 0

3 years ago