A person walking at 5/6 of his usual speed is 40 minutes late to his office. What is his usual travel time to his office?
Answer: 3 h 20 min.
Explanation
Let's say the person's usual travel time to his office is x minutes.
Since he is walking at 5/6 of his usual speed, his new speed is 5/6 of his usual speed.
The time taken to cover the same distance at this new speed is 6/5 of his usual time (since speed and time are inversely proportional).
So, the new time taken = (6/5)x
Since he is 40 minutes late, the new time taken is 40 minutes more than his usual time:
(6/5)x = x + 40
Simplifying the equation:
(1/5)x = 40
x = 200 minutes
Converting x to hours and minutes:
x = 3 hours 20 minutes
