If a pipe A can empty a full tank in x hours and two pipes C & D can fill the tank in y hours and z hours respectively then the part of tank filled in 1 hour, when all the pipes are opened together, is _________.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) →$\frac{xy+xz-yz}{xyz}$
Pipe A → Work Done = $\frac{-1}{x}$ [Emptying]
Pipe B → Work Done = $\frac{1}{y}$
Pipe C → Work Done = $\frac{1}{z}$
Total work done in 1 hour = $\frac{-1}{x}+\frac{1}{y}+\frac{1}{z}$ = $\frac{xy+xz-yz}{xyz}$