A car drove 200 miles using 10 gallons of fuel. Which operation should be used to compute the miles per gallon, which is 20?

To compute the miles per gallon, the operation that needs to be used is division. In this scenario, the total distance driven by the car, which is 200 miles, is divided by the total gallons of fuel used, which is 10 gallons. This calculation gives the result of miles per gallon.

Specifically, when you perform the calculation (200 miles ÷ 10 gallons), you arrive at 20 miles per gallon, which indicates that for every gallon of fuel, the car can travel 20 miles. This method of obtaining efficiency or rates, such as miles per gallon, is a standard application of division in mathematical contexts related to performance metrics.

The other operations—addition, subtraction, and multiplication—do not correctly apply here. Addition would inaccurately combine values without providing a rate, subtraction would imply a difference rather than a comparison of quantities, and multiplication would scale the values without representing how much distance is achieved per unit of fuel used. Thus, division is the most appropriate and necessary operation for calculating the efficiency of fuel usage in this context.