The tank at a gas station contained 400 gallons of gas. A tanker truck that contained 8100 gallons of gas filled the station's tank. After that the tanker truck had 4 times as much gas as the station's tank. How much gas did the tanker truck put into the station's tank?
Solution
Let x be the amount of gas in gallons that was put in the tank at the gas station to fill it up.
The tank now has 400 + x when it is full
The amount of x gallons given to the tank at the gas station was removed from the tanker.
The tanker truck now has 8100 – x
The tanker truck now has 4 times as much gas as the station's tank
8100 – x is 4 times as big as 400 + x
8100 – x = 4 (400 + x)
8100 – x = 1600 + 4x
8100 – x + x = 1600 + 4x + x
8100 = 1600 + 5x
8100 – 1600 = 1600 – 1600 + 5x
8100 – 1600 = 5x
6500 = 5x
x = 1300
1300 gallons of gas was added to the tank to fill it up
Sep 27, 22 08:34 AM