A car travels 15 kilometers west in 10 minutes. After reaching the destination, the car travels back to the starting point, again taking 5 minutes. What is the average velocity of the car?

Question

A car travels 15 kilometers west in 10 minutes. After reaching the destination, the car travels back to the starting point, again taking 5 minutes. What is the average velocity of the car?

Answer 1

What is the average velocity of the car?

120 KM per hour

Use the DISTANCE FORMULA D = RT, where D is the distance, R is the rate or the speed, and T

is the time in hours.

TRAVELING WEST: DISTANCE = 15 KM and the TIME is 10 minutes.

TRAVELING BACK(EAST): DISTANCE = 15 KM and the TIME is 5 minutes.

Total distance traveled is 30 KM, and the total time is 15 minutes or one-fourth of an hour.

The VELOCITY is the SPEED or RATE.

D = RT

30 = R(1/4)

120 = R (Multiplying both sides by 4.)

Therefore, the AVERAGE VELOCITY, SPEED, or RATE is 120 KM PER HOUR.

CHECKING:

If the car averages 120 KM per hour, then in 15 minutes(one-fourth of an hour), the car

traveled one-fourth of 120 KM, which equals (1/4)(120) = 30 KM.