Question

By walking at 3/4th of his usual speed , a man reaches office 20 minutes later than usual . What is his usual time ?

Please anyone not done wrong answer.​

Answer 1

Answer:

1 hour

Explanation:

Let the distance between his home and office be y, and his usual speed be x.

Given when he uses only 75 % of his speed, he reaches 20 minutes (1200 seconds) late.

So:

$\frac{y}{ \frac{3x}{4} } = \frac{y}{x} + 1200s$

therefore,

$\frac{4y}{3x} - \frac{y}{x} = 1200s$

$\frac{y}{3x} = 1200s$

$\frac{y}{x} = 3600s$

Since y/x = original time taken = 3600s = 1 hour

The answer will be 1 hour