A man travelled a distance of 150 km in 18 hours. He travelled partly on foot at 5 km/h and partly on bicycle at 10 km/h. What is the distance travelled on bicycle?

A man travelled a distance of 150 km in 18 hours.

Total distance = 150 km

total time = 18 hours

He travelled partly on foot at 5 km/h and partly on bicycle at 10 km/h.

Let's assume that he travelled 't' hours by foot.

then travelled by bicycle = (18-t)

So total distance =  speed by foot $$\times$$ t + speed by bicycle $$\times$$ (18-t)

150 = 5t+10(18-t)

30 = t+2(18-t)

t+36-2t = 30

2t-t = 36-30

t = 6

So the distance travelled on bicycle = speed by bicycle $$\times$$ (18-t)

= 10 $$\times$$ (18-6)

= 10 $$\times$$ 12

= 120 km