2021 · Q102
If the ratio of speeds of 'A' and 'B' is 5: 6 and 'B' allows 'A' a start of 70 metres in a 1.2 km race, who will win the race and by what distance?
General Mental Ability, Quantitative Aptitude and StatisticsNumber system and arithmetic
- A'A' wins by 30 m.
- B'B' wins by 200 m.
- C'B' wins by 130 m.
- DThe race finishes in a dead heat.
Explanation
Let the speeds of A and B is 50 m/s and 60 m/s respectively. B allows A start of 70 m in a 1.2 km race; That means A covers 1130 m and B covers 1200 m. Time in which A covers 1130 m = 1130/50 = 22.6 sec And, Time in which B covers 1200 m = 1200/60 = 20 sec It is evident that B wins the race and A takes 2.6 sec more than B to finish the race. ∴Distance by which B wins the race = 2.6 × 50 = 130 m