In a 1500 m race, X beats Y by 100 m and X beats Z by 240 m. By what distance does Y beat Z in the same race?
Explanation:
- In a 1500 m race:
- X beats Y by 100 m ? When X finishes 1500 m, Y has run 1400 m.
- X beats Z by 240 m ? When X finishes 1500 m, Z has run 1260 m.
- To compare Y and Z:
- When Y runs 1400 m, Z runs (1260/1500) × 1400 m = 1176 m.
- So, when Y finishes 1400 m, Z is at 1176 m.
- Therefore, Y beats Z by 1400 - 1176 = 224 m in a 1400 m race.
- But we want the distance Y beats Z in the full 1500 m:
- When Y finishes 1500 m, Z has run (1260/1500) × 1500 = 1260 m.
- So, Y beats Z by 1500 - 1260 = 240 m.
- That can't be, as that's how much X beats Z. Let's check again.
- When X finishes, Y is at 1400 m and Z at 1260 m.
- The times for X, Y, Z to finish their respective distances are equal.
- To find Y vs Z fairly:
- Y runs 1400 when X runs 1500.
- In that time, Z runs (1260/1500) × 1400 = 1176 m.
- In a 1400 m race, Y beats Z by 1400 - 1176 = 224 m.
- None of the options precisely matches 224 m. Let's compare with options:
- Option 1: 160 m
- Option 2: 140 m
- Option 3: 150 m
- Option 4: 200 m
- So, the correct answer from options is NOT 150 m; 224 m is not listed.
- The best method to check:
- Y’s speed = 1400/1500 = 14/15 times X's speed.
- Z’s speed = 1260/1500 = 21/25 times X's speed.
- Relative to Y:
Z’s speed = (21/25) ÷ (14/15) = (21/25) × (15/14) = (21×15)/(25×14) = 315/350 = 9/10.
- In a 1500 m race, Z covers (9/10)×1500 = 1350 m.
- So, Y beats Z by 1500 - 1350 = 150 m.
- Final calculation matches Option 3.
Option 3: 150 m is the correct answer.