When comparing the performance of two competitors in a race or any timed activity, always start by calculating their individual speeds using the formula \( \text{Speed} = \frac{\text{Distance}}{\text{Time}} \). Once you have their speeds, you can compute the distance each person covers in the same amount of time. This allows you to directly compare their performances and calculate the difference in distance. In this problem, after calculating each person's speed, we found how far Rahul had traveled in the same time Amit finished the race and then computed the distance by which Amit beats Rahul.
Amit's race completion time was 20 seconds, resulting in a speed of:
Speed of Amit = \( \frac{\text{Distance}}{\text{Time}} = \frac{700}{20} = 35 \, \text{m/s} \).
Rahul completed the race in 25 seconds, giving him a speed of:
Speed of Rahul = \( \frac{\text{Distance}}{\text{Time}} = \frac{700}{25} = 28 \, \text{m/s} \).
In the 20 seconds Amit took to finish, Rahul covered:
Distance covered by Rahul = Speed of Rahul \(\times\) Time = \( 28 \times 20 = 560 \, \text{m} \).
The margin by which Amit won is the difference in distance:
Distance = \( 700 - 560 = 140 \, \text{m} \).
Amit defeated Rahul by 140 m.