Model 3 Opening both taps and leaks Section-Wise Topic Notes With Detailed Explanation And Example Questions

Question : 1

Two pipes A and B can fill a tank in 6 hours and 8 hours respectively. If both the pipes are opened together, then after how many hours should B be closed so that the tank is full in 4 hours?

a) $8/3$ hrs

b) 2 hrs

c) $2/3$ hrs

d) 1hrs

Question : 2

A water tap fills a tub in ‘p’ hours and a sink at the bottom empties it in ‘q’ hours. If p < q and both tap and sink are open, the tank is filled in ‘r’ hours; then

a) r = p - q

b) r = p + q

c) $1/r = 1/p + 1/q$

d) $1/r = 1/p - 1/q$

Question : 3

A tank can be filled by two pipes in 20 minutes and 30 minutes respectively. When the tank was empty, the two pipes were opened. After some time, the first pipe was stopped and the tank was filled in 18 minutes. After how much time of the start was the first pipe stopped?

a) 12 minutes

b) 10 minutes

c) 5 minutes

d) 8 minutes

Question : 4

Two pipes, P and Q can fill a cistern in 12 and 15 minutes respectively. Both are opened together, but at the end of 3 minutes, P is turned off. In how many more minutes will Q fill the cistern ?

a) 8$1/4$ minutes

b) 8 minutes

c) 7 minutes

d) 7$1/2$ minutes

Question : 5

A tank has a leak which would empty the completely filled tank in 10 hours. If the tank is full of water and a tap is opened which admits 4 litres of water per minute in the tank, the leak takes 15 hours to empty the tank. How many litres of water does the tank hold ?

a) 7200 L

b) 1200 L

c) 2400 L

d) 4500 L

Question : 6

Three pipes A, B and C can fill a tank in 6 hours. After working together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is

a) 16

b) 14

c) 10

d) 12