knight247 wrote:A tank is fitted with an inlet which takes 1 hour to completely fill the empty tank. The tap was turned on when the tank was empty. When the tank was half filled , it developed a leak and as a result it took totally 65 minutes to fill the tank. As soon as the tank got filled completely, the tap was turned off but the leakage continued. How long will it take for the leakage to empty the tank completely.
Sorry but don't have answer options on this one. Also don't have an OA. Would appreciate if the
answer can be explained step by step in detail...thanks
Let tank = 60 units.
Rate of tap = w/t = 60/60 = 1 unit per minute.
Time for tap to fill half the tank = w/r = 30/1 = 30 minutes.
Since the total time is 65, time to fill the remaining half of the tank is 65-30 = 35 minutes.
Thus, rate with leak = w/t = 30/35 = 6/7 units per minute.
Rate of leak = Rate of tap alone - Rate of tap with leak = 1- 6/7 = 1/7 units per minute.
Time for leak to empty the full tank = w/r = 60/(1/7) = 420 minutes = 7 hours.
Last edited by
GMATGuruNY on Tue Jul 12, 2011 3:54 pm, edited 1 time in total.
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