Correct Answer - Option 1 : 24 km/hr.
Given:
Distance by car driving (x) = 30 km/hr.
Returns to the starting point (y) = 20 km/hr.
Formula used:
Average speed = (2xy)/(x + y)
Calculation:
(2 × 30 × 20)/(30 + 20) km/hr.
⇒ (2 × 30 × 20)/50 km/hr.
⇒ 24 km/hr.
∴ The average speed is 24 km/hr.