To calculate the number of gallons of gas you can buy for $3.15 using whole numbers, we need to determine how many gallons you can purchase with a whole dollar amount.
For example, if you have $3.00 to spend:
\[ \text{Gallons} = \frac{\text{Total Money}}{\text{Price per Gallon}} = \frac{3.00}{3.15} \approx 0.95 \text{ gallons} \]
If you have $4.00 to spend:
\[ \text{Gallons} = \frac{4.00}{3.15} \approx 1.27 \text{ gallons} \]
If you have $5.00 to spend:
\[ \text{Gallons} = \frac{5.00}{3.15} \approx 1.59 \text{ gallons} \]
If you have $6.00 to spend:
\[ \text{Gallons} = \frac{6.00}{3.15} \approx 1.90 \text{ gallons} \]
If you have $7.00 to spend:
\[ \text{Gallons} = \frac{7.00}{3.15} \approx 2.22 \text{ gallons} \]
If you have $8.00 to spend:
\[ \text{Gallons} = \frac{8.00}{3.15} \approx 2.54 \text{ gallons} \]
If you have $9.00 to spend:
\[ \text{Gallons} = \frac{9.00}{3.15} \approx 2.86 \text{ gallons} \]
If you have $10.00 to spend:
\[ \text{Gallons} = \frac{10.00}{3.15} \approx 3.17 \text{ gallons} \]
The question asks for whole number dollar amounts. The maximum number of gallons you can buy with whole dollar amounts under $3.15 is 2 gallons (with $6.30, which is not a whole number increment).
In whole dollar amounts:
- $3: you get 0 gallons.
- $4: you get 1 gallon.
- $5: you get 1 gallon.
- $6: you get 1 gallon.
- $7: you get 2 gallons.
- $8: you get 2 gallons.
- $9: you get 2 gallons.
- $10: you get 3 gallons.
So, for either $7, $8, or $9, you can buy a maximum of 2 gallons in whole dollars. To sum it up, the number of gallons you can purchase in whole number of dollars is either 1 or 2 gallons, depending on the dollar amount.