# If B is Used for Half the Time and A & B Fill it Together :

A large tanker can be filled by two pipes A & B in 60 minutes & 40 minutes respectively. How many minutes will it takes to fill the tanker from empty state if B is used for half the time and A & B fill it together for the other half:

- 30 mins
- 15 mins
- 20 mins
- None of these

**Answer: (1) 30 mins**

**Explanation:-
**Pipe A can be filled a tank = 60 min

Then, pipe A can be filled a tank in a min = 1/60 min

Pipe B can be filled a tank = 40 min

Pipe B can be filled a tank in a min = 1/40

Pipe A and B can be filled a tank in a min = (1/60 + 1/40)

= (2 + 3)/120

= 5/120

= 1/24

If B is used for half the time and A & B fill it together for the other half.

Then, 1 (1 /24 + 1/40)/2

= 1 (10 + 6)/240 x 2

= 16/240 x 2

= 2/30 x 2

= 1/30

Then, 30 min will it take to fill the tank.

Hence, the answer is (1) 30 mins.