The answer would be 18.2 gallons because they used up 5.8 gallons, they still have 12.4 gallons that they did not use and in order to get the original amount of gas they had before the trip, you would add up 12.4 and 5.8 to get the Original amount. Hope this helps.
Answer:
12.5
Step-by-step explanation:
For this case we have the following variables, let:
x: The greater integer
y: The minor integer
We have to:

Thus, we have a system of two equations with two unknowns. To solve, we follow the steps below:
Step 1:
We add both equations:


Thus, the smallest integer is 
Step 2:
We substitute "y" in any of the equations and clear x:

Thus, the largest integer is 
So:

Anwer:
Integer minor, 
Integer greater,
X is the unknown value. The word "of" means to multiply. 40% in decimal form is 0.40. So "40% of a value" means "0.40x".
20=0.40x
Divide both sides by 0.40:
x=50
Ok! First add the 13 over to the other side, which makes 4x<24.
Then divide 24 by 4, which gives you x<6.