clearly A beats B by 9 seconds. distance covered by B in 9 sec =(100÷45)×9m=20m A beats B by 20 m
In 100 m race, A covers the distance in 36 seconds and B in 45 seconds.
Clearly, A beats B by (45-36)=9 seconds
Speed of B = Distance/Time
=100/45 m/s
Distance Covered by B in 9 seconds = Speed × Time
= (100/45) × 9 = 20 metre
i.e., A beats B by 20 metre