Question

Pipes a and b can fill a tank in 12 min and 16 min respectively. both are kept open for 'n' min and then b is closed and a fills the rest of the tank in 5 min. the time 'n' after which b was closed is:

Answer 1

n((1/12)+(1/6))+5(1/12)=1

on taking LCM and solving this quation further we get n=4