1. Four pipes can fill a reservoir in 15, 20, 30 and 60 hours respectively. The first one was opened at 6 AM, second at 7 AM, third at 8 AM and the fourth at 9 AM. When will the reservoir be filled? (b)
a. 12 pm noon
b. 1 pm
c. 2 pm
d. 3 pm
2.Two pipes A & B can fill the tank in 12 hours and 36 hours respectively. If both the pipes are opened simultaneously, how much time will be required to fill the tank? (b)
a. 6 hours
b. 9 hours
c. 12 hours
d. 15 hours
3. A cistern can be filled by a tap in 4 hours while it can be emptied by another tap in 9 hours. If both the taps are opened simultaneously, then after how much time cistern will get filled ? (c)
a. 7 hours
b.7.1 hours
c.7.2 hours
d.7.3 hours
4.Two pipes A and B can fill a tank in 15 hours and 20 hours respectively while third pipe C can empty the full tank in 25 hours. All the three pipes are opened in the beginning. After 10 hours, C is closed. In how much, will the tank be full? (a)
a. 12 hrs
b. 13 hrs
c. 16 hrs
d. 18 hrs
5.Two pipes can fill a tank in 8 hrs & 6 hrs respectively. If they are opened on alternate hours and if pipe A gets opened first, then in how many hours, the tank will be full? (b)
a. 6 hrs
b. 7 hrs
c. 8 hrs
d. 14 hrs