Q75
A runs 7/4 times as fast as B. If A gives B a start of 300 m, how far must the winning post be if both A and B have to end the race at same time?
A runs times as fast as B. If A gives B a start of 300 m, how far must the winning post be if both A and B have to end the race at same time?
A.
1400 m
B.
700 m
AnswerC.
350 m
D.
210 m
Answer: Option B
Solution
Answer: Option B
Solution:
| . | A | B | Reason (ST=D) |
| Speed | 7 | 4 | Given |
| Time | 4 | 7 | Since, Speed ∝ |
| Distance | 4 | 7 | Distance ∝ time |
Now,
7x - 4x = 300 (A runs 7x m and B runs 4x)
x = 100
7x = 7 × 100 = 700 m
Winning post is 700 m away, As A runs 700 m to complete the race.