An inlet pipe A originating from a river can fill a reservior in 30 days.And an outlet pipe B,which is capable of emptying the completely filed reservoir in 50 days ,drains out the water from the reservoir to an irrigation canal.The pipes are opened on alternate days with A.On which day from the beginning will the reservoir get completely filled for the first time?
Show answer & explanation
Correct answer: B
Explanation
Correct Answer is option 2 i.e. 147th
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Understanding |
Application |
Calculation |
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A can fill the tank in 30 days and B can empty it in 50 days. |
Suppose, Capacity of tank = 150 units |
LCM of 30 and 50 = 150 |
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Efficiencies = Work/Time |
Efficiency of A = 5
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⇒ 150/30 = 5 |
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Efficiencies = Work/Time |
Efficiency of B = -3
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⇒ 150/50 = 3 |
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The pipes are opened on alternate days starting with A. |
2 days’ work = 2 units Hence, 146 days’ work = 146 units |
⇒ 5 – 3 = 2 ⇒ 73 × 2 = 146 |
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A will work on 147th day. |
A will fill remaining 4 units in 147th day. Hence, tank will get filled in 147th day. |
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