A RED car took 2 h to travel from town X to town Y. His average speed for the whole journey was 40 km/h. For the first of the journey, he traveled at an average speed of 50 km/h. Find his average speed for the second part of the journey

Solution

2 X 40 = 100 km

100 X (1/4) = 25 km

100 – 25 = 75 km

time taken for (1/4) of journey = 25/50

= 1/2 h

time taken for 2nd part of journey = 2.5 – 0.5

= 2h

Average speed = 75km / 2

= 37.5km/h

or 2.5 X 40 = 100 km

100 x (3/4) = 75

75 ÷ 2 = 37.5 km/h