Question

Three pipes A B and C can fill a swimming pool in 6 hours. After working on it together for 2 hours, C is closed and A and B fill the remaining part in 7 hours. Find the number of hours taken by C alone to fill the swimming pool.​

Answer 1

Step-by-step explanation:

Part time in 2 hours=62=31

Remaining part=(1−31)=32.

∴(A+B)'s 7 hour's work=32

(A+B)'s 1 hour's work=212

∴ C's hour's work={(A+B+C)'s 1 hour's work}−{(A+B)'s 1 hour's work}

=(61−212)=141

∴ C alone can fill the tank in 14 hours.

Answer 2

Answer:

Part time in 2 hours

$= \frac{2}{6} = \frac{1}{3}$

Remaining part

$= (1 - \frac{1}{3}) = \frac{2}{3}$

So (A+B)'s 7 hour work

$= \frac{2}{3}$

Their one hour work

$= \frac{2}{21}$

C's hour work ={(A+B+C})'s 1 hour work-A+B's 1 hour work

$= ( \frac{1}{6} - \frac{2}{21}) \\ \\ = \frac{1}{14}$

Hope it helps you from my side