TIaO - Part 1

Number Theory Level 1

An inlet (a pipe that lets water enter a tank) can fill a tank in $12$ hours. Another inlet can fill the same tank in $15$ hours. A third inlet can fill the tank in $10$ hours. If the three inlets are opened simultaneously, in how many hours will the tank be full?

This problem is part of the set Tank Inlets and Outlets - Work Problems.