a cyclist cycles for 2h at a speed of 27km/h. he then cycles for 11/2h at an average speed of 20km/have. fin the average speed for the whole journey.

total trip = 2(27) + (11/2)(20) km

= 164 km

total time = 2+11/2 or 7.5 hours

average speed = 164/7.5 or appr 21.87 km/h