Question

a man covers 120 km of his journey at at 40 km/hr , next 145 km at 58 km/hr and last 35 km half an hour . find his average speed during whole journey

Answer 1

Average speed= Total distance travelled/ Total time taken

Total distance travelled= 120+145+35=300 km

Total time taken:-
(1)time=Distance/speed
= 120/40=3 hours
(2)time=Distance/speed
= 145/58=2.5 hours
(2)time=Distance/speed
= 35/0.5 =70 hours
Total time taken= 3+2.5+70= 75.5 hours.

Average speed= Total distance travelled/ Total time taken
= 300/75.5
=40 km/h

Therefore, his average speed is 40 km/h