2013 AMC 10B Problems/Problem 8
Problem
Ray's car averages 40 miles per gallon of gasoline, and Tom's car averages 10 miles per gallon of gasoline. Ray and Tom each drive the same number of miles. What is the cars' combined rate of miles per gallon of gasoline?
Solution
Let both Ray and Tom drive 40 miles. Ray's car would require gallon of gas and Tom's car would require
gallons of gas. They would have driven a total of
miles, on
gallons of gas, for a combined rate of