Question

A fish tank has 150 gallons of water and is being drained at a rate of 1/2 gallon each second. A second fish tank has 120 gallons of water and is being filled at a rate of 1/4 gallon each second. After how many seconds will the two fish tanks have the same amount of water?

Answer 1

Answer: 40 seconds

Explanation:

This is basically a very simple algebra problem.

Let x be the number of seconds it takes for the statement to be true

120 + x/4 = 150 - x/2

Add x/2 to both sides:

120 + 3x/4 = 150

Subtract 120 from both sides:

3x/4 = 30

Therefore x = 40.

Solve similar problems with an equation, where the variable is the thing you need to find.