In a 500 m race, the ratio of the speeds of two contestants A and B is 3 : 4. A has a start of 140 m. Then, A wins by:
60 m
40 m
20 m
10 m
Explanation:
To reach the winning post A will have to cover a distance of $\left(500 - 140\right)$m, i.e., 360 m.
While A covers 3 m, B covers 4 m.
While A covers 360 m, B covers$ \left(\dfrac{4}{3} \times 360\right) $m= 480 m.
Thus, when A reaches the winning post, B covers 480 m and therefore remains 20 m
behind.
$\therefore$ A wins by 20 m.