Please help!! Math II

Q2. A train travels at a constant speed of 45 m/s. a) Calculate the distance travelled by the train in:

alex41 [277]

Answer:

i) 1350 m

ii) 5400 m

Step-by-step explanation:

<u>Formula for Speed</u>

$\boxed{\sf Speed=\dfrac{Distance}{Time}}$

Rearrange the formula so that Distance is the subject:

$\implies \sf Distance = Speed \times Time$

<h3><u>Question (i)</u></h3>

Given:

Speed = 45 m/s (meters per second)
Time = 30 seconds

Substitute the given values into the formula for distance:

$\implies \sf Distance = 45 \times 30 = 1350\:m$

<h3><u>Question (ii)</u></h3>

Given:

Speed = 45 m/s (meters per second)
Time = 2 minutes

As the time is given in a different unit of time as the speed, we must first convert the time into seconds:

1 minute = 60 seconds

⇒ 2 minutes = 60 × 2 = 120 seconds

Therefore:

Speed = 45 m/s (meters per second)
Time = 120 seconds

Substitute the values into the formula for distance:

$\implies \sf Distance = 45 \times 120 = 5400\:m$

3 0

7 months ago

Read 2 more answers

The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day.

valina [46]

Answer:

A sample of 179 is needed.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.85}{2} = 0.075$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.075 = 0.925$ , so Z = 1.44.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

A previous study found that for an average family the variance is 1.69 gallon?

This means that $\sigma = \sqrt{1.69} = 1.3$

If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?

A sample of n is needed, and n is found for M = 0.14. So

$M = z\frac{\sigma}{\sqrt{n}}$

$0.14 = 1.44\frac{1.3}{\sqrt{n}}$

$0.14\sqrt{n} = 1.44*1.3$

$\sqrt{n} = \frac{1.44*1.3}{0.14}$

$(\sqrt{n})^2 = (\frac{1.44*1.3}{0.14})^2$

$n = 178.8$

Rounding up

A sample of 179 is needed.

7 0

2 years ago

3.2x + 7.9 + 8.2 + 6.7x<br> Simplify the expressions. (not equations!) <br> Please help ASAP.

Temka [501]

Answer:

9.9x + 16.1

Step-by-step explanation:

SImplify using like terms

Simplify:

3.2x + 7.9 + 8.2 + 6.7x
3.2x + 6.7x + 7.9 + 8.2
9.9x + 16.1

-Chetan K

4 0

1 year ago

Find the slope of each line.<br> 1) y=− x−5<br> 2) y=− x−1

poizon [28]

1) slope = -1

2) slope = -1

5 0

3 years ago

asma owns $52000 in student loans for college. if the loan will be repaid in 5.5 years and the interest rate charged is 6.75% th

Ahat [919]

I=$52,000 R=6.75% T=5.5 years P=$19,305

3 0

2 years ago