If a car travels 300 miles on 10 gallons of gas, what is the car's mileage in miles per gallon?

To determine the car's mileage in miles per gallon, you need to divide the total distance traveled by the total amount of gas consumed. In this case, the car travels 300 miles and uses 10 gallons of gas.

Calculating the mileage involves the following steps:

1. Take the total distance: 300 miles.

2. Divide that by the total gallons of gas used: 10 gallons.

So, the calculation works out as follows:

[

\text{Mileage} = \frac{\text{Distance}}{\text{Gas Used}} = \frac{300 \text{ miles}}{10 \text{ gallons}} = 30 \text{ miles per gallon (mpg)}

]

Thus, the car's mileage is 30 mpg, which matches the provided answer. This means that for every gallon of gas the car uses, it can travel 30 miles. This metric is a standard measure to evaluate fuel efficiency and is crucial for comparing different vehicles’ performance regarding fuel consumption.