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A water tank can be filled by a tap in 30 minutes and another tap can fill it in 60 minutes. If both the taps are kept open for 5 minutes and then the first tap is closed, how long will it take for the tank to be full ?
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- 20 minutes
- 25 minutes
- 30 minutes
- 45 minutes
- 20 minutes
Correct Option: D
On the basis of given details in question ,
| Part of the tank filled by both taps in 5 minutes = 5 |  | + |  | ||
| 30 | 60 |
| Part of the tank filled by both taps in 5 minutes = 5 | | | = 5 × | = | |||
| 60 | 60 | 4 |
| Remaining part = 1 - | = | that is filled b second top. | ||
| 4 | 4 |
| ∴ Time taken = | × 60 = 45 minutes | |
| 4 |
