Correct Answer - Option 1 : 56(12/23)
Given:
A man travels from A to B at a speed of 50 km/hr
He returns back by increasing his speed by 30%
Formula used:
Average speed = total distance covered/total time taken
Distance = speed × time
Calculation:
Let the distance travelled from A to B be ‘D’
Time taken to travel from A to B = D/50
Return speed = 130/100 × 50 = 65 km/hr
Time taken to travel back from B to A = D/65
Total distance = D + D = 2D
Total time taken = D/50 + D/65 = (13D +10D)/650 = 23D/650
Average speed = 2D/23D × 650
⇒ 1300/23
⇒ \(56{12\over 23}\)
∴ Average speed during the whole journey is \(56{12\over 23}\).
