A large water reservoir has two outlet pipes, a small one and a large one. It takes 7 hours to empty the rese

Question

A large water reservoir has two outlet pipes, a small one and a large one. It takes 7 hours to empty the reservoir when only the small outlet pipe is open. It takes 2 hours to empty the reservoir when only the large outlet pipe is open. About what fraction of the reservoir will be emptied in one hour if both the pipes are open?

Answer 1

What fraction will the reservoir be emptied in one hour

Let

1/7 the smaller pipe

1/2 the larger pipe

- - - - - - - - - - - - - - - - - - - - - - - - -

1/7 + 1/2

The common denominator is 14

2/14 + 7/14

9/14 is the fraction

The answer is 9/14

The solution set is { 9/14 }

Answer 2

Hi,
its pretty simple. Well, my solution is. I dont know if it is right or wrong.

First the small pipe empties the resevoir in 7 hrs.
So, it empties X/7 of the reservoir in 1 hour.
Considering X as the size of reservoir.

Similary, the large pipe empties X/2 in 1 hour.

In 1 hour when both of them are open, the reservoir empties at
X/2 + X/7 per hour.
ie., the fraction is 1/2 + 1/7 = 9/14.

Peace out.

Answer 3

Actually, 9/14 IS correct. The question was what fraction of the reservoir will be emptied in one hour, not how many hours it takes to empty the reservoir completely (which would be 14/9 hours).

Answer 4

I'm guessing it'll be about 9/14 empty. In one hour from the large pipe it'll be 1/2 empty. And from the small pipe it'll be 1/7 empty. Find the common denominator (14) then add the two. I guess.

Answer 5

if it takes 7 hours to drain through the small pipe, in 1 hour 1/7 of the resevoir will go through that pipe. If it takes 2 hours to drain through the large pipe, in 1 hour 1/2 of the resevoir will go through that pipe. The answer is 1/2 + 1/7 which is 9/14.

Answer 6

I in basic terms began a three/4 sleeve 3 days in the past!! i've got been given the define achieved....and that i've got enormous call outlines on the decrease back of each arm and the I even have this different one on the very top portion of my decrease back it is prob approximately 5-6 inces huge, 2-3 inches long...and definite I plan on getting many greater!

Answer 7

THE INVERSE OF 1/7 +1/2 = 14/9 HRS

9/14 IS NOT CORRECT

Answer 8

i figure just under 60 percent