# Math Help - Pipe Filling

1. ## Pipe Filling

Hi,

I have 3 Pipes. First pipe can fill a tank in 10 minutes, second pipe can fill the tank in 15 minutes and 3rd pipe can fill the tank in 20 minutes. What formula can I apply to calculate the time to fill the tank, if all the three pipes are opened simultaneously?

Thanks!

2. Originally Posted by ManuLi
Hi,

I have 3 Pipes. First pipe can fill a tank in 10 minutes, second pipe can fill the tank in 15 minutes and 3rd pipe can fill the tank in 20 minutes. What formula can I apply to calculate the time to fill the tank, if all the three pipes are opened simultaneously?

Thanks!
Hi ManuLi,

Pipe 1 fills $\frac{1}{10}$ of the tank in 1 minute.
Pipe 2 fills $\frac{1}{15}$ of the tank in 1 minute.
Pipe 3 fills $\frac{1}{20}$ of the tank in 1 minute.

$\frac{1}{10}+\frac{1}{15}+\frac{1}{20}=\frac{1}{t}$

Solve for $t$