Question

a runs twice as fast as B. runs trice as fast as C. the distance covered by c in 72 minutes, will be covered by A in :
1-18 minutes
2-24 minutes
3- 16 minytes
4-12 minutes

Answer 1

C takes 72 mins 
B runs thrice as fast.⇒b takes 72/3 mins=24 mins
A runs twice as fast as B⇒A takes 24/2=12 mins.

So the answer to the question is 4-12 mins

Answer 2

Given = A runs twice as fast as B
B runs thrice as fast.
C takes 72 mins 

Now A.T.Q

B = 72 / 3 =  24

and A = 24/2 = 12 minutes

Hence the option 4 - 12 minutes is correct .