Final answer:
The question requires knowledge of the car's miles per gallon to determine how many more miles it can travel with a half-empty 14-gallon tank. Without this key piece of information, we cannot calculate the answer.
Step-by-step explanation:
The question asks how many more miles a car can travel if its 14-gallon fuel tank is halfway empty and the car averages 50 miles per hour. First, since the tank is halfway empty, 7 gallons are remaining. The car's average speed is not directly relevant to the amount of miles it can cover on the remaining fuel unless we are asked for the time it would take to cover those miles.
To answer this, we calculate the car's miles per gallon (mpg) and then multiply that figure by the number of gallons left. However, we lack the car's mpg, which is needed to solve this problem. Without this information, we cannot determine the exact answer. Therefore, no specific answer can be given based on the information provided.