Pipe D can fill a tank in $15$ hours, and pipe E can fill the same tank in $18$ hours. Pipe F can empty the tank in $25$ hours. Initially, pipes D and...
Question
Pipe D can fill a tank in $15$ hours, and pipe E can fill the same tank in $18$ hours. Pipe F can empty the tank in $25$ hours. Initially, pipes D and E are opened together for $5$ hours. After that, pipe E is closed, and pipe F is opened along with pipe D. Find the total time taken by pipes D and F together to fill the remaining part of the tank.