Problema Solution
Two medical pumps can fill a methadone dosing tank in 90 minutes when working together. Alone, the second pump takes 3 times as long as the first to fill the tank.
How many minutes would it take the first pump to fill the tank?
Answer provided by our tutors
Let
x = the time (in minutes) the first pump needs to fill the tank
1/x tank per minute is the rate of the first pump
3x = the time (in minutes) the second pump needs to fill the tank
1/(3x) tank per minute is the rate of the second pump
1/90 tank per min is the together rate
Now we can write:
1/x + 1/(3x) = 1/90
........
click here to see the equation solved for x
........
x = 120 min
The first pump needs 120 minutes to fill the tank.