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If a boy walks from his house to school at the rate of 4 km per hr, he reaches the school 10 minutes earlier than the scheduled time. However if he walks at the rate of 3 km per hr, he reaches 10 minutes late. Find the distance of his school from his house.
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- 3.5 km
- 3 km
- 4 km
- 4.5 km
Correct Option: C
Let the distance be x kms.
∴ Time taken at 4 km per hr. t1
| = | hrs. | |
| 4 |
Time taken at 3 km per hr.t2
| = | hrs. | |
| 3 |
Difference in timings
= 10 + 10 = 20 minutes
| or | = | hour | ||
| 60 | 3 |
| ∴ | − | = | |||
| 3 | 4 | 3 |
| ⇒ | = | ||
| 12 | 3 |
| ⇒ | = | ||
| 12 | 3 |
∴ x = 4 km.
Hence the required distance
= 4 kms.
