You drive to the store at 20 kmph and return by the same route at 30 kmph. Discounting the time spent at the store, what was your average speed ?
Correct Answer: 24 kmph
Explanation:
Average speed=total distance/total time
Let distance to store be K
then, total time =(K/20)+(K/30)=K/12
and, total time =(2K)
so average speed= 2K / (K/12) = 24kmph.
