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?
Answers
Explanation: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.