Multiple choice

A pipe can fill a tank in 10 hours. After half the tank isfilled, four more similar pipes are opened in the tank. Findthe total time in which tank will be filled completely?

  1. 6 hr

  2. 7 hr

  3. 7.5 hr

  4. 6.5 hr

  5. 8 hr
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pipe fills 1/10 per hour. Half tank takes 5 hours. Remaining half tank is filled by 5 pipes at 5/10 = 1/2 per hour. Time for remaining half = (1/2) / (1/2) = 1 hour. Total time = 5 + 1 = 6 hours.

AI explanation

Using the basic pipe capacity method, the first pipe fills half the tank in 5 hours. The remaining half tank equals 0.5 of the total capacity, and with five similar pipes open, their combined rate is 5 divided by 10, which is 0.5 of the tank per hour. The time to fill the rest is 0.5 divided by 0.5, equaling 1 hour. The total time is the initial 5 hours plus this 1 hour, resulting in 6 hr.

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