Question

$A$ is twice a fast as $B$ and $B$ is thrice as $C$'s. The journey covered by $C$ in $42$ minutes, will be covered by $A$.

• A. $14$ minutes
• B. $7$ minutes
• C. $28$ minutes
• D. $54$ minutes

Answer 1

The correct option is B $7$ minutes

Let C's speed$=x$ kmph

B's speed$=3x$ kmph

& A's speed$=6x$ kmph

therefore Ratio of speeds of A, B, C$=6x:3x:x=6:3:1$

Ratio of times taken$=1/6:1/3:1=1:2:6$

If C takes $6$ min, A takes $1$ min

If C takes $42$ min,

A takes $\left(1/6^{\ast }42\right)$min$=7$min Ans.