Word problem

Question

The octane rating of a gasoline is a measure of the amount of isooctane in the gas. Manufacturers recommend using 93-octane gasoline on returned motors. How much 87-octane gas and 95-octane gas should Yousef mix in order to make 10 gallons of 93-octane gas for his returned Ford F-150?

Answer 1

a + b = 10 ------> a = 10 - b

87a + 95b = 93(10)

 

87(10 - b) + 95b = 930

870 - 87b + 95b = 930

8b = 60

b = 7.5

 

a = 10 - 7.5 = 2.5

 

Hope this helps!