A cistern can be completely drained by a pipe in 6 hours. It can be filled by two pipes in 4 hours and 5 hours, respectively. How many hours will the empty cistern take to fill if all the pipes are running?

If x is the time to fill it, which of the following equations could be used to solve for t?

4x + 5x - 6x = 1

15x + 12x - 10x = 60

4x + 5x = 20

Question

11 July, 22:07

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Answers (1)

Know the Answer?

Tiffany Acevedo · Answer 1

X/4 + x/5 - x/6=1

make the denominator the same:

15x/60 + 12x/60 - 10x/60=1

17x=60

x=60/17=3.53 hours

the second choice is the correct answer.