Dear student,
here,
u = 18 km/hr = 18 x 5/18 m/s = 5 m/s
v = 36 km/hr = 10 m/s
so, acceleration a = (v - u) / t = (10-5) / 5 = 1 m/s2
now, the total distance travelled will be
s = ut + (1/2)at2
or
s = 5x5+ (1/2)1.(5)2
or
s = 25+ 12.5
thus,
s = 37.5m
Regards.