Archie’s gas tank is 1/3 full. If Archie adds 3 gallons of gas to the tank, it will be 1/2 full.What is the capacity in gallons of Archie’s tank?

Step 1: Understand the problem. Archie's gas tank is currently 1/3 full. When he adds 3 gallons, it becomes 1/2 full. We need to find the total capacity of the tank.

Step 2: Set up an equation. We know that the difference between 1/2 and 1/3 of the tank's capacity is equal to 3 gallons. So, we can write this as: 1/2x - 1/3x = 3.

Step 3: Solve the equation. To make it easier, you can first find a common denominator for 1/2 and 1/3, which is 6. So, the equation becomes: 3x/6 - 2x/6 = 3. Simplify this to x/6 = 3.

Step 4: Solve for x. Multiply both sides of the equation by 6 to solve for x. This gives you x = 18.

So, the capacity of Archie's gas tank is 18 gallons.