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.