All categories

3 years ago

How far will a train travel in 5 hours if it travels at 80 miles per hour?

Mathematics

1 answer:

Lunna [17]3 years ago

7 0

Answer:

C. 400 miles

Step-by-step explanation:

In each hour, it travels 80 miles. (That is the meaning of "80 miles per hour.") So you can add up the distances over a period of 5 hours:

80 miles + 80 miles + 80 miles + 80 miles + 80 miles

After the first sum (80+80=160), you can see what the correct answer will be. Continuing, you find the sum to be ...

= 400 miles

___

Multiplication was invented to make repeated addition easier.

5 × 80 miles = 400 miles

_____

Strictly speaking, you are multiplying numbers with units here:

(5 h) × (80 mi/h) = 400 mi·h/h = 400 mi . . . . . . the units h/h cancel

You might be interested in

Which is closest to the value of w in the triangle below?

mr Goodwill [35]

Answer: B. 2.5 in

Step-by-step explanation:

From the given right angle triangle,

the hypotenuse of the right angle triangle is the unknown side.

With m∠32 as the reference angle,

the adjacent side of the right angle triangle is 4 in

the opposite side of the right angle triangle is w

To determine w, we would apply

the tangent trigonometric ratio which is expressed as

Tan θ = opposite side/adjacent side. Therefore,

Tan 32 = w/4

w = 4tan32 = 4 × 0.625

w = 2.5 in

8 0

3 years ago

Past experience has indicated that the breaking strength of yarn used in manufacturing drapery material is normally distributed

vlabodo [156]

Answer:

95% two-sided confidence interval on the true mean breaking strength is (94.8cm, 99.2cm)

Step-by-step explanation:

Our sample size is 11.

The first step to solve this problem is finding our degrees of freedom, that is, the sample size subtracted by 1. So

$df = 11-1 = 10$ .

Then, we need to subtract one by the confidence level $\alpha$ and divide by 2. So:

$\frac{1-0.95}{2} = \frac{0.05}{2} = 0.025$

Now, we need our answers from both steps above to find a value T in the t-distribution table. So, with 10 and 0.025 in the two-sided t-distribution table, we have $T = 1.812$

Now, we find the standard deviation of the sample. This is the division of the standard deviation by the square root of the sample size. So

$s = \frac{4}{\sqrt{11}} = 1.2060$

Now, we multiply T and s

$M = Ts = 1.812*1.2060 = 2.19/tex]For the lower end of the interval, we subtract the sample mean by M. So the lower end of the interval here is[tex]L = 97 - 2.19 = 94.81 = 94.8$ cm