# Thread: (Basic Algebra) Major Help on my Test that is Due Tom.!!! I hate Words Problems

1. ## (Basic Algebra) Major Help on my Test that is Due Tom.!!! I hate Words Problems

An inlet pipe can fill a large water tank in 240
minutes. An outlet pipe can empty the same
water tank in 5 hours. Given an
empty water tank, activate both pipes.
Question: How many minutes will it be before
the tank is completely filled?
Round to the nearest minute.
Can you show me work, so i know how to do it... Thank u Thank u Thank u

2. Originally Posted by Sweetie
An inlet pipe can fill a large water tank in 240
minutes. An outlet pipe can empty the same
water tank in 5 hours. Given an
empty water tank, activate both pipes.
Question: How many minutes will it be before
the tank is completely filled?
Round to the nearest minute.
Can you show me work, so i know how to do it... Thank u Thank u Thank u
5 hours = 300 mins.

So each minute the inlet pipe will fill $\displaystyle \frac{1}{240}$ of the tank and the outlet pipe will empty $\displaystyle \frac{1}{300}$ of the tank.

Put them together, you get every minute

$\displaystyle \frac{1}{240} - \frac{1}{300}$ of the tank will be filled.

$\displaystyle \frac{1}{240} - \frac{1}{300} = \frac{300}{240 \times 300} - \frac{240}{300 \times 240}$

$\displaystyle = \frac{300 - 240}{72000} = \frac{60}{72000} = \frac{1}{1200}$.

So every minute, $\displaystyle \frac{1}{1200}$ of the tank will be filled.

So you would need 1200 minutes to fill the tank, or 20 hours.

Of course, no-one would fill a tank this way... it's too wasteful.

4. lol yay i was right but i did it a different way... I used x as the amount of hours.

If it takes 4 hours to fill the tank then in 1 hour the 1/4 of the tank is filled.

If it takes 5 hours to empty the tank then in 1 hour 1/5 of the tank is empty.

so you want to find the total number of hours it takes for a whole tank.

x/4-x/5=1

and solved for x