Calculating the average speed

Question

'A cyclist travelling at an average speed of u km/h takes t hours to travel from A to B. On reaching B, the cyclist rests for 0.1t hours before returning from B to A along the same route. If the cyclist reaches A 2t hours after first setting out, find an expression for the average speed of the cyclist on the return journey.'

 

 

Answer 1

tu = AB

The return trip took 0.9t (2t - t - 0.9t)

AB = 0.9tr

tu = 0.9tr

u = 0.9r

1.11...u ≈ r