An oil tank contains 220.2 gallons of oil. Whenever the amount of oil drops below 90 gallons, an alarm sounds. If 145.3 gallons are pumped into a delivery truck, how many gallons must be pumped back into the tank in order to shut off the alarm? I'm doing a remedial math course and I need help with a lot of questions..

Start with 220.2 gallons of oil. Add 145.3 more gallons 220.2 + 145.3 = 365.3 Now, figure out how much be pumped out to get down to 90. Call it x 365.3 - x = 90 Rearranging our equation, we have: x = 365.3 - 90 x = 275.3