Question

Two pipes X and Y can fill a tank in 6 hrs and 4 hrs respectively. If both the pipes are opened simultaneously, how much time both pipes will take to fill the tank?

1. 10 hrs
2. 4.5 hrs
3. 2.4 hrs
4. 5 hrs
5. None of these

Answer 1

Correct Answer - Option 3 : 2.4 hrs

Given:

Pipe X can fill the tank alone in 6 hr

Pipe Y can fill the tank alone in 4 hr

Concept:

Let, Pipe A can fill a tank in x hrs

⇒ Pipe A can fill a tank in 1 hr = 1/x

Calculation:

Pipe X can fill the tank in 1 hr = 1/6

Pipe Y can fill the tank in 1 hr = 1/4

⇒ Pipe (X + Y) can fill the tank in 1 hr together = (1/6) + (1/4) = (5/12)

⇒ Total time taken to fill the tank = 12/5 = 2.4 hr

∴ The required answer is 2.4 hours.