2020 · Q28
The ratio of speeds of X and Y is 5 : 6. If Y allows X a start of 70 m in a 1.2 km race, then who will win the race and by what distance?
Elementary MathematicsTime, Speed and Distance
- AX wins the race by 30 m
- BY wins the race by 90 m
- CY wins the race by 130 m
- DThe race finishes in a dead heat
Explanation
With speeds 5v and 6v: X runs 1200 − 70 = 1130 m in time 1130/5v = 226/v, while Y runs 1200 m in 1200/6v = 200/v. Y finishes first. In that time X covers 5v × 200/v = 1000 m, reaching the 70 + 1000 = 1070 m mark — 130 m short of the finish. So Y wins by 130 m.