Question 692382
First pipe fills the tank in 48 mins
So in 1 minute, it will fill 1/48 part of the tank.
Second pipe fills the tank in 1 hr 12 mins or in 72 mins
So in 1 minute, 2nd pipe will fill 1/72 parts of the tank.
When both the pipes fill the tank, in 1 minute, they will fill
{{{1/18 + 1/72}}} parts of the tank
= {{{(3 + 2)/144}}}
= {{{5/144}}} parts
Therefore, the tank will be full in 1 / (5/144) minutes
= 144/5 mins
= 22 mins 48 secs when both the pipes fill it