Mohan goes to office from home at a speed of 20 km/h and returns to home from office at a certain speed. If the average speed is 24 km/h, then what is the speed while returning?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 30 km/h
Formula used:
Average speed = 2xy/(x + y) ---- (1)
Where, x and y are the speed and distance remains the same.
Calculations:
Let the speed while returning be y.
Using equation (1), we get
⇒ 24 = (2 × 20 × y)/(20 + y)
⇒ (20 + y) × 3 = 5y
⇒ 60 + 3y = 5y
⇒ 2y = 60
⇒ y = 30 km/h