# How Much Time will be Taken by B to Fill the Tank? If

Pipe A alone can fill a tank in 8 hours. Pipe B alone can fill the same tank in 6 hours. If both the pipes are opened but after 2 hours pipe A is closed, then pipe B will fill the tank in

- 6 hours
- 7/2 hours
- 4 hours
- 5/2 hours

**Answer: (4) 5/2 hours.**

**Explanation:-**

Pipe A alone can fill a tank = 8 hours

therefore, Pipe A alone can fill a tank in 1 hour = 1/8

Pipe B alone can fill a tank = 6 hours

Therefore, Pipe B alone can fill a tank in a hour = 1/6

Both pipe can fill the tank = 2(1/8 + 1/6)

= 1/ 4 + 1 /3

= 7/12

Part of empty tank = 1 – 7/12

= (12 – 7)/12 = 5/12

B can fill the tank = 5 x 6 /12 = 5/2 hours.

Hence, the answer is (4) 5/2 hours.