One pump fills a tank in 20 hours and another in 15 hours. When a third pump is added the tank fills in 6 hours. Find out how long it takes the 3rd pump to fill the tank alone.
Mathematics · High School · Tue Nov 03 2020
Answered on
Pipe A fills the tank in 20 hours
Pipe B fills the tank in 15 hours
Pipe A,B,C fills the tank in 6 hours
Total work = efficiency * time
we know, total work = LCM of (20, 15,6)
= 60
Now, efficiency of A+B+C = 60/6
= 10
efficiency of A = 60/20
= 3
efficiency of B = 60/15
= 4
A+B+C =10
4+3+C = 10
C =10 - 7
C = 3
Time taken by C to fill the tank = Total work/efficiency
= 60/3
= 20 hours
Thus, time taken by pipe C alone to fill the tank is 20 hours.