Question

Priyanka cycles To her school at an average speed 12 kilometre per hour it takes 20 minutes to reach the school
if she wants to reach school in 15 minutes find her average speed

Answer 1

Speed = 12 km/h
and time = 20/60 = 1/3 hours.

So, Distance = Speed * time
                      = 12*1/3
                      = 4 km

So, To travel 4 km in 15 min = 1/4 h

     Speed = 4/1/4
     Speed = 16 Km/h

Answer 2

v=12km/h=1/5km/min
t=20min
s=vt=20*1/5
s=4km
new time=15min=15/60=1/4hr
s=4km
v=4/1/4=16km/h