Question

A motorist travels regularly between two
towns. He usually takes 5 hours when
travelling at a certain speed. He finds
that if he increases his average speed by
15 km/h, the journey takes 1 hour less.
Find his usual speed.​

Answer 1

Let the usual speed be x

5x=(5-1(x+15)

5x=4(x+15)

5x=4x+605x-4x=60

x=60..