A bike rider covers 100 km at a speed of 75 km/h. At what speed does the rider have to drive for the next hour to get an average speed of 90 km/h?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 110 km/h
As we know that
The average speed = Total distance covered/Total time taken
Given that
A bike rider covers 100 km at a speed of 75 km/h.
Let Rider speed for the next one hour = S km/h
The average speed = 90 km/h
Calculations
90 = (100 + S)/(100/75 + 1)
100 + S = 90 × (4/3 + 1) = 30 × 7 = 210
S = 210 - 100 = 110 km/h