Math Question

Question

A family has two cars. During one particular week, the first car consumed
40
gallons of gas and the second consumed
35
gallons of gas. The two cars drove a combined total of
1700
miles, and the sum of their fuel efficiencies was
45
miles per gallon. What were the fuel efficiencies of each of the cars that week?

Answer 1

Read carefully to understand the situation.  If we are looking for fuel efficiencies, that is, miles per gal for each car, let x = mpg for car 1 and y = mpg for car 2.  We know the sum of the efficiencies is 45, so

 

x+y = 45. 

 

We also know the distance they went, and the amount of gas each one used.  To find the distance each car went, we would take the miles per gal. time the number of gals.  So 

40 x  the distance car 1 went, and 35 y is the distance the second car went.   The total , that is, the answer when you add the two, is 1700.  

 

40x + 35 y = 1700

x + y = 45

 

Can you solve this now?  

 

Keep trying.