Syntel Company Numerical Ability Pipes and Cistern

Two taps can fill a cistern in 10 and 8 hours respectively. A third tap can empty it in 15 hours . if all the taps are opened together , the cistern will be filled in
[A] 5 h
[C] 12 h
[B] 6 h
[D] 6 6/19 h

Read Solution (Total 1)

the answer is optn D)
a+b's 1hr work=1/10+1/8
third tap empty =1/15 of tank
all taps opend together 1/10+1/8-1/15 of tank==19/120
1hr=19/120 of tank
120/9 hrs=complet tank=6 6/19
12 years agoHelpfull: Yes(14) No(2)

Syntel Other Question

Two fill pipes A and B can fill a tank in 30 and 20 hours respectively. Pipe B alone is kept open for half the time and both pipes are kept open for the remaining time. In how many hours the tank will be completely full?
[A] 12 h
[C] 14 h
[B] 13 h
[D] 15 h Two fillings pipes can fill a cistern in 10 and 12 min. respectively and when the waste pipe is open, they can together fill it in 15 min. The waste pipe can empttyy the full cistern in?
[A] 8 min
[C] 8 4/7 min
[B] 7 min
[D] 7 1/2 min