Pipe A can fill a cistern in 6 hours and pipe B can fill it in 8 hoursBoth the pipes are opened and after two hours pipe A is closedHow much time will B take to fill the remaining part of the tan?

Answer 1

Answer:

10/3 hour = 3 Hour and 20 minutes

Solution:

the volume of cistern (V) = 1 volume unit

flow rate of pipe A = 1/6 V/hour

flow rate of pipe B = 1/8 V/hour

Volume filled = flow rate * time

in the first two hours the volume filled = 1/6 * 2 + 1/8 *2 = 7/12 V.

Remaining Volume = 1-7/12=5/12

the folw rate after two hours = 1/8 (just pipe B)

required time for pipe B to fill the cistern = Volume / flow rate of the pipe B

= 5/12 divided by 1/8

= 5/12 * 8/1 = 10/3 hours = 3 and 1/3 hours = 3 hours and 20 minutes.

Check:

if the answer is correct the volume should be 1:

Total volume = 1/6*2 + 1/8*2 + 1/8*10/3 = 1.

so, the answer is correct.

Cheers!