Multiple choice

If 5 pipes are required to fill a tank in 1 hour, how many more such pipes are required to fill the same tank in 15 minutes?

  1. 5

  2. 10

  3. 15

  4. 20
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Work = 5 pipes * 60 minutes = 300 pipe-minutes. To fill in 15 minutes, we need 300 / 15 = 20 pipes total. We already have 5, so we need 15 more.

AI explanation

Using the unitary method, if 5 pipes fill the tank in 60 minutes, one pipe would take 300 minutes. To fill the same tank in 15 minutes, the total number of pipes required is 300 divided by 15, which is 20 pipes. Therefore, the number of additional pipes needed is 20 minus 5, resulting in 15 more pipes.

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