A gas tank is 1/4 full. Abby adds 4 gallons and now it is 5/8 full. How many gallons does the tank hold?

let the tank hold x gallons

(1/4)x + 4 = (5/8)x
times everybody by 8
2x + 32 = 5x
-3x = -32
x = 10 2/3 gallons

To find out how many gallons the gas tank holds, we need to use the given information about the tank's level before and after Abby adds 4 gallons.

Let's say the total capacity of the gas tank is "x" gallons.

According to the problem, initially, the tank is 1/4 (or 1/4 * x) full. Then, Abby adds 4 gallons to it, which makes it 5/8 (or 5/8 * x) full.

We can set up an equation to solve for "x" by equating the two expressions we have:

1/4 * x + 4 = 5/8 * x

To get rid of the fractions, we can multiply both sides of the equation by 8:

8 * (1/4 * x + 4) = 8 * (5/8 * x)

Simplifying, we have:

2x + 32 = 5x

To isolate "x," let's subtract 2x from both sides of the equation:

32 = 3x

Finally, divide both sides by 3:

x = 32 / 3

Therefore, the gas tank holds approximately 10.67 gallons.