Answer: after 40 seconds, the two tanks will have the same amount of water.
Step-by-step explanation:
Let x represent the number of seconds after which both tanks will have the same amount of water.
A fish tank has 150 gallons of water and is being drained at a rate of 1/2 gallons each second. It means that the number of gallons of water that would be in the tank after t seconds is
150 - 0.5t
A second fish tank has 120 gallons and it is being filled at a rate of 1/4 gallons each second. It means that the number of gallons of water that would be in the tank after t seconds is
120 + 0.25t
For the volume of both tanks to he the same, then
120 + 0.25t = 150 - 0.5t
0.25t + 0.5t = 150 - 120
0.75t = 30
t = 40 seconds
