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If three pipes P, Q, and R together can empty full tank in 25 minutes, if P is twice as efficient as Q and Q is twice as efficient as R then in how much time R will empty 60% of the tank?1. 90 minutes2. 105 minutes3. 95 minutes4. 114 minutes |
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Answer» Correct Answer - Option 2 : 105 minutes Given: P, Q, and R can empty a tank in 25 minutes P is twice as efficient as Q Q is twice as efficient as R Concept used The efficiency of people/taps is equal to what they can do/destroy or fill/empty the given task per hour/minute/day. Calculation: Let tank emptied by R in a minute be x units, Q be 2x units and P be 4x units Tank emptied by R in 25 minutes = 25x units Tank emptied by Q in 25 minutes = 2x × 25 = 50x units Tank emptied by P in 25 minutes = 4x × 25 = 100x units Total tank emptied by them together in 25 minutes = 25x + 50x + 100x = 175x Time taken to empty the tank by R = (Total units)/(Tank emptied in 1 minute) R will empty 60% of 175x = 105x in 105x/x ⇒ 105 mins ∴ R will empty 60% of the tank in 105 min |
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