Question 171279
One hose can fill an empty tank in 7 hours. A second hose can fill the empty tank in 12 hours. How long will it take to fill the empty tank if both hoses are used? Write an equation and solve.

1/7 + 1/12 = 1/x

Can you solve for x?

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I received your reply.


1/7 + 1/12 = 1/x

Multiplying all terms on both sides by the LCD, which is 84x, we get the following:

12x + 7x = 84

We now have a linear equation.

So, solve for x.

19x = 84

x = 84/19

x is approximately 4.42, which can be rounded off to the nearest tenths place to be 4.40 (about 4 hours and 40 minutes).

Together, both hoses can fill the empty tank in 4 hours and 40 minutes (slightly less than 5 hours).

Did you follow?