Question

A cistern has two inlets A and B which can fill it in 12 hours and 15 hours, respectively. An outlet can empty the full cistem in 10 hours. If all the three pipes are opened together in the empty
cister, how much time will they take to fill the cistern completely ?​

Answer 1

Step-by-step explanation:

A=12 Efficiency=60/12=5

B=15 Efficiency=60/15=4

lcm(12,15,10)=60(total work)

C=10 Efficency60/10=6

All together =(5+4)-6=9-5=3

Time =total work/total efficiency=60/3=20 days