A boy walks a distance of 30 m in 1 minute and another 30 m in 1.5 minute. Describe the type of motion of the boy and find his average speed in m s^-1.

The motion of the boy is non-uniform.
total distance travelled = 30 m + 30 m = 60 m
total time taken = 1 min + 1.5 min = 2.5 min
1 min = 60 sec
2.5 min = 2.5 x 60 = 150 sec
Average speed = ?

$\text{Average Speed} = \dfrac{\text{Total distance travelled}}{\text{total time taken}} \\[1em] \text{Average Speed} = \dfrac{\text{60}}{\text{150}} = 0.4 \text{m s}^{-1}$

So, average speed of the boy = 0.4 m s^-1.