A man started 20 min late and travelling at a speed of 1 1/ 2 times of his usual speed reaches his office in time. The time taken by the man to reach his office at his usual speed is?
Correct Answer: 1 h
Explanation:
Let usual speed of a man is V and time is t h.
By the formula, V1t1 = V2t2
Vt = 11/2 V(t - 20/60)
⇒ t = 3/2(t - 1/3)
⇒ 3/2 t - t = 1/2
∴ t = 1 h
Hence, the time taken by the man to reach his office at his usual speed is 1 h.