How much gas did each of them use?

Question

Gus, antonio, and sam drove their cars to a lake where they like to fish. For the trip, antonio used 1 more gallon of gas then gus, and sam used twice as much gas as antonio. Together they used 39 gallons of gas. How much gas did each of them use

Answer 1

Let x = the number of gallons of gas that Gus used

Let x + 1 = the number of gallons of gas that Antonio used

Let 2(x + 1) = the number of gallons of gas that Sam used

x + x + 1 + 2x + 2 = 39

4x + 3 = 39

4x = 36

x = 9 gallons that Gus used

Antonio: x + 1 = 10

Sam: 2x + 2 = 20