Multiple choice

Rakesh covers x km at 10 km/hr and 2x km at 20 km/hr. What is his average speed?

  1. 12 km/hr

  2. 15 km/hr

  3. 16 km/hr

  4. 18 km/hr

  5. Data insufficient

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Average speed = Total distance / Total time. Total distance = x + 2x = 3x. Total time = (x/10) + (2x/20) = x/10 + x/10 = 2x/10 = x/5. Average speed = 3x / (x/5) = 15 km/hr.