Question

$A$ and $B$ are $12.5$ kms apart. If they travel in opposite directions, they meet after half an hour. If they travel in the same direction, they meet after $2.5$ hours. If $A$ travels faster than $B$, then the speed of $A$ is

• A. $10$ km/hr
• B. $12.5$ km/hr
• C. $15$ km/hr
• D. $20$ km/hr

Answer 1

Answer: (A)

$10$ km/hr

Let $S_1$ be speed of $A$ and $S_2$ be speed of $B$ also $S_1>S_2$
$\therefore 1.S_1+1.S_2=25km....\left(1\right)$ (When travels in opposite direction)
When travels in same direction the distance travelled has difference of $25km$.
i.e., $5.S_1+5.S_2=25km....\left(2\right)$ From (1) and (2) $S_1=10km/hr$