Two inlet pipes can fill a cistern in 10 and 12 hours respectively and an outlet pipe can empty 80 gallons of water Per hour

Two inlet pipes can fill a cistern in 10 and 12 hours respectively and an outlet pipe can empty 80 gallons of water Per hour. All the three pipes working together can fill the empty cistern in 20 hours. What is the capacity (in gallons) of the tank?

(a)          360

(b)          300

(c)           600

(d)          900

 Sol:

C = 8 → 80 gallon

60 → 600 gallons