Question 14427
Let r=regular, p=premium
First set up the two equations
8r+12p=27.84
p=r+0.17
Substitute for p
8r+12(r+0.17)=27.84
Distribute
8r+12r+2.04=27.84
Combine like terms
20r+2.04=27.84
Subtract 2.04 from both sides of the equation
20r=25.80
Divide both sides of the equation by 20
r=1.29
Now plug in the value for r into one of the original equations
p=1.29+0.17
p=1.46
One gallon of regular unleaded gasoline is $1.29
One gallon of premium unleaded gasoline is $1.46