Ravi travels from City A to City B. If Ravi drives his car at ​$$\frac{2}{7}$$​ of his normal speed, then he reaches City B 30 minutes late.
Find the time (in minutes) that Ravi would have taken to travel from City A to City B if he drove at his normal speed.​

Correct option is B

Given:

Ravi drives at $$\frac{2}{7}$$​ of his normal speed and is 30 minutes late.

Concept Used: 

For distance constant.

If speed decreases, time increases inversely.

Solution: 

Speed ratio =  7      :      2 

time ratio  =   2      :      7 

now, 

7x - 2x  = 30 min. 

5x = 30 min.

x = 6 min. 

time taken if he drove by normal speed ;

= $$2 \times 6 = 12 \ min.$$​​