A car's fuel efficiency (miles per gallon) varies inversely ...

Question Analysis
This problem applies the concept of inverse variation to a real-world context, specifically the relationship between a car's fuel efficiency and its speed.

Key Concept Explanation
Inverse variation is expressed as or . Here, fuel efficiency (in miles per gallon) varies inversely with speed (in miles per hour).

Step-by-step Solution
1. Use the given values and to find :