Hari travels from City A to City B. If Hari drives his car at 1/8 of his normal speed, then he reaches City B 21 minutes late. Find the time (in minutes) that Hari would have taken to travel from City A to City B if he drove at his normal speed.

Correct option is B

Given:

When Hari drives at $$\frac{1}{8}$$​ of his normal speed, he is 21 minutes late.

Concept Used:

Time is inversely proportional to speed.

Solution: ​

Let the time taken at normal speed be t minutes

So if speed becomes $$\frac{1}{8}$$​, time becomes 8t 

The difference between slow time and normal time = 21 minutes

So, 

8t - t = 21

7t = 21 

t =$$\frac{21}{7}$$​ = 3

Thus, Time at normal speed = 3 minutes