Final answer:
Marvin needed approximately 14.28 gallons of gas last week.
Step-by-step explanation:
To find out how much gas Marvin needed last week, we can set up an equation using the given information. Let x represent the amount of gas Marvin needed last week.
Marvin needed 163.1% more gas this week than last week, which means he needed 1.631 times the amount he needed last week. So, we can set up the equation: 1.631x = 23.3
To solve for x, we divide both sides of the equation by 1.631: x = 23.3 / 1.631 ≅ 14.28
Therefore, Marvin needed approximately 14.28 gallons of gas last week.