Model 1 Basic Pipes & Cisterns problems Section-Wise Topic Notes With Detailed Explanation And Example Questions

Question : 1

Two pipes can fill a cistern separately in 10 hours and 15 hours. They can together fill the cistern in

a) 9 hours

b) 6 hours

c) 7 hours

d) 8 hours

Question : 2

A cistern is provided with two pipes A and B. A can fill it in 20 minutes and B can empty it in 30 minutes. If A and B be kept open alternately for one minute each, how soon will the cistern be filled ?

a) 120 minutes

b) 121 minutes

c) 110 minutes

d) 115 minutes

Question : 3

A cistern can be filled with water by a pipe in 5 hours and it can be emptied by a second pipe in 4 hours. If both the pipes are opened when the cistern is full, the time in which it will be emptied is :

a) 20$1/2$ hours

b) 9 hours

c) 18 hours

d) 20 hours

Question : 4

A pipe can fill a tank in x hours and another can empty it in y hours. They can together fill it in (y > x)

a) ${xy}/{x - y}$ hours

b) ${xy}/{y - x}$ hours

c) x - y hours

d) y - x hours