Question

Find the average speed if a bus if it moves from point A to B at a speed of 30kmph amd returns at a speed of 50kmph.

Pls answer urgently
Regards CJ

Answer 1

LCM of 30 and 50 is 150
So let's assume the distance from A to B be 150 km.

Now time taken from A to B is 150/30 = 5 hrs.

Time taken from B to A is 150/50 = 3 hrs.

Total distance travelled = 150+150 = 300 km

Total time = 5+3 = 8 hrs.

Average speed = 300/8
= 37.5km/hr.

Why did we take the distance equal to the LCM of 30 and 50?

Ans: We did it because that would make our calculations very easy as we are getting the time in integer values 5 & 3 and not any point value which would increase the calculation time.