Question

three pipes a, b and c together can fill an empty tank in 4 hours. after 1 hr, c is closed and the tank is full in 6 more hrs. find the time in which c alone can fill the empty tank?

Answer 1

Answer:

8 hours

Step-by-step explanation:

Pipe A, B and C can fill the tank in 4 hours

1 hour = 1/4 of the tank

Find the amount of work A and B needs to do after 1 hour

Amount of work = 1 - 1/4 = 3/4 of the tank

Pipe A and Pipe B can do fill 3/4 of the tank in 6 hours

3/4 of the tank = 6 hours

1/4 of the tank = 6 ÷ 3 = 2 hours

4/4 of the tank = 2 x 4 = 8 hours

Pipe A and B can fill the tank in 8 hours

1 hour = 1/8 of the tank

Find the amount of work C can do in an hour

1 hour = 1/4 - 1/8 = 1/8 of the tank

Find the amount of time C need:

1/8 of the tank = 1 hour

8/8 of the tank = 1 x 8 = 8 hours

Answer: C needs 8 hours to fill the tank alone.