Answer:
12 and a half minutes ago
Explanation:
In five minutes, the pool drained 180-120=60 gallons of water. This means that the pool loses 60/5=12 gallons of water per minute.
You can make the equation 270-12x=120, where x is the amount of minutes passed.
Subtract 270 on both sides to get -12x=-150
Divide both sides by -12
x=150/12 which is 12.5
Therefore, x=12.5 or 12 and a half minutes ago