A runs four times as fast as B. If A gives B a start of 90 meters, how far must the goal on the race course be so that A and B reach it at the same time ?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 120 meters
Let the goal be d metres from A’s start. B starts 90 m ahead, so B has to run d − 90 m. Both reach the goal together, so in the same time A covers d and B covers d − 90; A is four times as fast:
\( \displaystyle d=4(d-90) \)
\( \displaystyle 3d=360 \)
\( \displaystyle d=120\text{ meters} \)