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Question

Daim can walk at 4 km/h and ride his bike at 20 km/h. He takes 24 minutes less when he rides his bike from his house to the school than he walks. What is the distance, in km, from his house to the school?

Answer 1

v = walking speed = 4 km/h

u = bike speed = 20 km/h

 

d = vt

d = u(t - 24/60) = u(t - 0.4)

 

vt = u(t - 0.4)

4t = 20(t - 0.4)

8 = 16t

t = 8/16 h = 0.5 h

 

d = vt = (4 km/h)(0.5 h) = 2 km