A is twice fast as B and B is thrice fast as C is. The journey covered by C in 3/2 hours will be covered by A is:

Explanation:-

Let speed of C = X
Then Speed of B = 3X
Then Speed of A = 6X
Ratio of the speed of A and C = 1:6
So, Greater the speed less time taken in journey.
C’s speed is 6 times less than A So A will take ¹/₆ of the total time taken C to covered same distance.
So, Time taken by A = ³/_(2*6) = ¼ hours = 15 minutes.