Question

A man complete s 30 km oof a journey at6 km\h and the remaking 40 km of journey in 5 h then his average speed of the whole journey is

Answer 1

The speed of the person in case 1 is 6 Km/hr and the speed in the case 2 is 40/5= 8 Km/hr.      The average of the two speed is = 6+8 =14/2 = 7 Km/hr.
                                                                                      2

Answer 2

7 km/h is the average speed-
In first case -
speed- 6km/h
distance-30km
time taken-30kmph/6h=5hrs
in second case-
Distance-40km
time-5h
we know-
s=d/t
s=40km/5h
s=8km/h
total distance travalled = 30km+40 km=70km
now
average speed = (6km/h+8km/h)/2
average speed= 7km/h

check=7km/h x (5h+5h)
         = 70 km