Question

three pipes a,b,c can fill tank in 8 hr. after working at it for 2 hr a is closed and b,c fill the tank in 9 hr. what is the number of hours taken to fill the cistern by a

Answer 1

Answer:Part filled in 2 hours = 2/6 = 1/3. Remaining part = 2/3

(A + B)'s 7 hours' work = 2/3.

So, (A+B)'s 1 hr work = 2/21

Therefore C's 1 hour's work

= [(A+B+C)'s 1 hour]-[(A+B)'s 1 hr work]

=(1/6 - 2/21) = 1/14

C alone can fill the tank in 14 hours

Option 5)