Answer:
C. 20
Step-by-step explanation:
The order in which the members are selected is important. The first one selected is the president and the second is the vice president.
So we use the permutations formula to solve this question.
Permutations formula:
The number of possible permutations of x elements from a set of n elements is given by the following formula:
In this problem:
2 people are going to be chosen from a set of 5. So
So the correct answer is:
C. 20
Bernard’s walking speed is 140 meters per minute
Bernard’s walking speed is 8.4 kilometers per hour
Step-by-step explanation:
The pace length P is the distance between the rear of two consecutive footprints
The formula, n P = 140, gives an approximate relationship between n and P where,
We need to calculate Bernard’s walking speed in meters per minute and in kilometers per hour
∵ n = number of steps per minute
∴ n unit is number / minute
∵ P = pace length in meters
∴ P unit is meter
- That means n P unit is meters/minute
∴ n P represents the speed in meters per second
∵ The formula applies to Bernard’s walking
∵ His pace length is 0.80 meters
∵ n P = 140
∴ n(0.8) = 140
- Divide both sides by 0.8
∴ n = 175
- That means he moves 175 steps per minute
∵ The distance he walks in minute = 175 × 0.8 = 140 meters/minute
∴ His speed is 140 meters per minute
Bernard’s walking speed is 140 meters per minute
∵ 1 km = 1000 m
∵ 1 hour = 60 minutes
- Divide the meters by 1000 and the minute by 60 to change
from meters per minute to kilometers per hour
∴ His walking speed = ÷
- Change ÷ to × and reciprocal the fraction after the division sign
∴ His walking speed = ×
= 8.4 km/h
Bernard’s walking speed is 8.4 kilometers per hour
Learn more:
You can learn more about the speed in brainly.com/question/5461619
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