The boy walks a distance 30 m in 1 minute and another 30 m in 1.5 minute, it means the boy covers unequal distances in equal time intervals. Thus, the motion is non uniform.
Given,
Total distance travelled=(30+30) m
=60 m
Total time taken=(1+1.5) min
=2.5 min=150 sec
To find, Average speed
Average speed=Total distance coveredTotal time taken
=60 m150 sec
So, the average speed of car is 0.4 ms−1.