There are two inlets A and B connected to a tank. A and B can fill the

1.	There are two inlets A and B connected to a tank. A and B can fill the tank in 16 hours and 10 hours respectively. If both taps are opened alternatively for 1h, starting from A then how much time will the tank take to be filled?1. 12 hours 12 minutes2. 11 hours 45 minutes3. 12 hours 24 minutes4. 12 hours 15 minutes5. None of these
Answer» Correct Answer - Option 3 : 12 hours 24 minutes Given: The inlet pipe A can fill a tank in 16 hours and pipe B can fill in 10 hours. Concept Used: If a pipe can fill a tank in x hour, then in 1 hour 1/x part of the tank will be filled by the pipe. Calculation: Pipe A can fill the tank in 16 hour Part of the tank filled by pipe A in 1 hour = 1/16 Pipe B can fill a tank in 10 hours Part of the tank filled by B in 1 hour = 1/10 The part filled by (A + B) in 2 hours = 1/16 + 1/10 ⇒ (5 + 8)/80 ⇒ 13/80 Now, 6 × (13/80) = 78/80 ⇒ In 6 × 2 = 12 hours tank filled by 78/80 part Remaining is (1 - 78/80) part ⇒ 2/80 = 1/40 part After complete of 12 hours pipe A will be open To fill 1/16 part pipe A takes time 1 hour ⇒ To fill 1/40 part pipe A will take time (16/40) hour ⇒ (2/5) hour ⇒ 24 minutes [∵ 1 hour = 60 min] Total time needed to fill the tank (12 hours + 24 minutes) ⇒ 12 hours 24 minutes ∴ Starting from A 12 hours 24 minutes will take to fill the tank.

There are two inlets A and B connected to a tank. A and B can fill the tank in 16 hours and 10 hours respectively. If both taps are opened alternatively for 1h, starting from A then how much time will the tank take to be filled?1. 12 hours 12 minutes2. 11 hours 45 minutes3. 12 hours 24 minutes4. 12 hours 15 minutes5. None of these

Answer» Correct Answer - Option 3 : 12 hours 24 minutes

Given:

The inlet pipe A can fill a tank in 16 hours and pipe B can fill in 10 hours.

Concept Used:

If a pipe can fill a tank in x hour, then in 1 hour 1/x part of the tank will be filled by the pipe.

Calculation:

Pipe A can fill the tank in 16 hour

Part of the tank filled by pipe A in 1 hour = 1/16

Pipe B can fill a tank in 10 hours

Part of the tank filled by B in 1 hour = 1/10

The part filled by (A + B) in 2 hours = 1/16 + 1/10

⇒ (5 + 8)/80

⇒ 13/80

Now, 6 × (13/80) = 78/80

⇒ In 6 × 2 = 12 hours tank filled by 78/80 part

Remaining is (1 - 78/80) part

⇒ 2/80 = 1/40 part

After complete of 12 hours pipe A will be open

To fill 1/16 part pipe A takes time 1 hour

⇒ To fill 1/40 part pipe A will take time (16/40) hour

⇒ (2/5) hour

⇒ 24 minutes [∵ 1 hour = 60 min]

Total time needed to fill the tank (12 hours + 24 minutes)

⇒ 12 hours 24 minutes

∴ Starting from A 12 hours 24 minutes will take to fill the tank.