Question

A bus travelling the first one-third distance
at a speed of 10 km/h, the next one fourth at
20km/h and the remaining at 40 km/h. The
average speed of the bus is nearly.​

Answer 1

Answer:

If total distance is S then

Average speed = Total distance / Time

= S / (t1 + t2)

= S / [(S/(3 * 10)) + (S/(4 * 20)) + (5S/(12 * 40))]

...….....[∵ Time = Distance / Speed]

= 1 / (1/30 + 1/80 + 5/480)

= 17.7 kmph

In two significant figures average speed will be 18 kmph