What is the reciprocal of 7/2

A. What formula will be use to relate the data? Explain the part of the formula?

Alenkasestr [34]

9514 1404 393

Answer:

2.5 miles

Step-by-step explanation:

1A. The formula that applies to time/speed/distance problems is ...

distance = speed × time

The units of the numbers involved need to be compatible, which is to say the speed units need to be the ratio of distance units to time units.

The other applicable relationship is that the resultant speed in a body of water is the sum of the boat speed and the water speed. When they are in the same direction, the speeds add; when they are in the opposite direction, the net speed is their difference.

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1B, C. Since Tom is traveling upstream, his net speed is the difference between his paddling speed (8 mph) and the current (3 mph). That is, he makes headway upstream at the rate of 8-3=5 mph. This difference is the "speed" in the formula.

Note that the time is given in minutes, but the units of speed have time units of hours. It is easiest in this problem to translate the time in minutes to a time in hours. (30 min = 1/2 h) This is the "time" in the formula.

We can "let 'distance' represent the distance we're being asked to find in the problem statement."

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1D. Using the formula, we find ...

distance = (5 mi/h)(1/2 h)

This is the "formula" equation of part A with speed and time values filled in.

The solution to the equation is simply a matter of performing the indicated arithmetic.

distance = 2.5 mi

Tom would travel 2.5 miles in 30 minutes.

_____

<em>Additional comment</em>

You may see the above formula written a number of ways. Using single-letter variables, it is often written as ...

d = rt

where d represents distance, r represents speed, and t represents time. By using whole words for the variable names, I find less explanation is necessary.

By using units along with the numbers in the formula, the units of the answer "fall out". If they don't, then there has been a mistake. For example, if you use 30 minutes instead of 1/2 hour, your answer would be ...

(5 mi/h)(30 min) = 150 mi·min/h

These units are not distance units, so you know a mistake has been made. (The units multiply and/or cancel the same as any variable(s).)

5 0

3 years ago

Read 2 more answers

A) The cosine rule can be used to find the value of x in the triangle below.

BartSMP [9]

Answer:

see explanation

Step-by-step explanation:

(a)

(the side required )² = sum of squares of other 2 sides - ( 2 × product of other 2 sides and cos(angle opposite side required ) )

x² = 12² + 15² - (2 × 12 × 15 × cos71°)

(b)

x² = 144 + 225 - 360cos71°

= 369 - 360cos71° ( take square root of both sides )

x = $\sqrt{369-360cos71}$

≈ 16 cm ( to the nearest integer )

5 0

2 years ago

Ok so what is is the square root of 1234 i dot know

natita [175]

sqrt(1234) = 35.1283

you don't say how it should be rounded, so round off as needed

4 0

3 years ago

A student who is trying to write a paper for a course has a choice of two topics, a and

Kitty [74]

Say she chooses topic A. She needs at least one book to arrive on time. The probability that no books arrive on time is 0.1 x 0.1 = 0.01 so the probability that at least one book arrives on time is 1 - 0.01 = 0.99.
Say she chooses topic B. She needs at least two books to arrive on time. The probability of no books arriving on time is 0.1 x 0.1 x 0.1 x 0.1 = 0.0001. The probability of exactly one book arriving on time is 4 x 0.1 x 0.1 x 0.1 x 0.9 = 0.0036 (binomial probability distribution formula - the 4 comes from 4C1). So the probability of her not getting enough books is 0.0001 + 0.0036 = 0.0037 and the probability she does get the books she needs on time is 1 - 0.0037 = 0.9963.
So she should choose topic B.

4 0

3 years ago

A boy has 3 red , 6 yellow and 5 green marbles. In how many ways can the boy arrange the marbles in a line if:All marbles have d

Alenkasestr [34]

Answer: 8.72*10^10

Step-by-step explanation:

Total number of balls = 14

Now,

Make 14 lines.

_ _ _ _ _ _ _ _ _ _ _ _ _ _

In the first position, you can choose any ball from 14 balls. So,

14 _ _ _ _ _ _ _ _ _ _ _ _ _

In the second position, you can choose any ball from 13 balls. This is because you've already kept one ball in first position. So,

14 13 _ _ _ _ _ _ _ _ _ _ _ _

In the third position, you can choose any ball from 12 balls. So,

14 13 12 _ _ _ _ _ _ _ _ _ _ _

Do this until you fill all the place.

14 13 12 11 10 9 8 7 6 5 4 3 2 1

Multiply all of this.

14 *13 *12 *11 *10 *9 *8 *7 *6 *5 *4 *3 *2 *1

= 8.72*10^10

5 0

3 years ago