Two pipes A and B can fill a tánk in 24 hours and
120
hours
respectively. Harihar opéned the pipes A and B to fill an
empty tank and some times later he closed the taps A and B,
when the tank was supposed to be full. After that it was found
that the tank was emptied in 2.5 hours because an outlet pipe
C' connected to the tank was open from the beginning. I
Harihar closed the pipeC instead of closing pipes A and Bthe
remaining tank would have been filled in :
(a) 2 hours
(c) 6 hours
(b) 8 hours(d) 4 hours