To determine whether Spencer can get more or less gas at Fuel Stop compared to Gas World given that he has $20 to spend, we need to consider the following:
- Spencer bought gas at Gas World on Saturday for an amount that he used up (let's call the price per gallon \( P_G \)).
- On Sunday, he bought the same amount of gas from Fuel Stop for less money (let's call the amount of gas he bought \( G \)) at a price per gallon \( P_F \), where \( P_F < P_G \).
Since he now has $20 to spend on gas:
- At Gas World, the cost for \( G \) gallons was \( P_G \times G \).
- At Fuel Stop, the cost for \( G \) gallons was \( P_F \times G \).
The key point is that since \( P_F < P_G \), Spencer spent less money at Fuel Stop for the same amount of gas. Therefore, his expenditure at Fuel Stop was less than his expenditure at Gas World, suggesting that he saved some money.
With the remaining money from his previous expenditure, which would be the difference between $20 and the cost he incurred at Fuel Stop, he could potentially buy additional gas.
Thus, since he can buy more gas at Fuel Stop due to the lower price, Spencer will be able to get more gas at Fuel Stop than at Gas World with his $20 budget.