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Bunuel
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A hotel bathtub can be filled in 30 minutes and drained in 45 minutes. 21 Jul 2020, 04:52
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E
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15% (low)

Question Stats:

80% (01:13) correct 20% (01:24) wrong based on 94 sessions

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A hotel bathtub can be filled in 30 minutes and drained in 45 minutes. How many minutes will it take to fill the tub if a maid forgets to close the drain valve?

A. 40
B. 45
C. 60
D. 75
E. 90
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E
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A hotel bathtub can be filled in 30 minutes and drained in 45 minutes. 21 Jul 2020, 05:01
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Total work per minute 1\30 - 1\45 = 1\90

Total time to do whole work = 90 minutes

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A hotel bathtub can be filled in 30 minutes and drained in 45 minutes. 21 Jul 2020, 05:42
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1/30 - 1/45
=1/90

Answer - E
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A hotel bathtub can be filled in 30 minutes and drained in 45 minutes. 22 Jul 2020, 02:03
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Bunuel
A hotel bathtub can be filled in 30 minutes and drained in 45 minutes. How many minutes will it take to fill the tub if a maid forgets to close the drain valve?

A. 40
B. 45
C. 60
D. 75
E. 90
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Solution


    • Let us assume that that the work involved in filling complete tub is 90 units (L.C.M. of 30 and 45).
      o So, rate of filling the bathtub \(= \frac{90}{30} = 3\) units per minute.
      o And , rate of draining the bathtub \( = \frac{90}{45} = 2 \) units per minute.
    • Thus, the effective rate of filling the bathtub \(= 3 -2 = 1\) unit per minute.
    • Now, time taken to fill the bathtub \(= \frac{work \space involved \space in \space filling \space the \space bathtub}{ the \space effective \space rate \space of \space filling \space the \space bathtub} = \frac{90}{1} = 90\) minutes
Thus, the correct answer is Option E.
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