Question

The cost of a gallon of gasoline g is $3.25 less than 2 times the cost of a gallon diesel d. If a gasoline cost $3.95, what is the cost of s gallon of diesel? Write an equation and solve

Answer 1

How about this to start:

(cost of gallon of gas) = 2(cost of gallon of diesel) - $3.25
this is the same as:
g = 2d-3.25

And you are given that g = 3.95, so you can substitute that in for g and solve for d.

(3.95) = 2d - 3.25
3.95+3.25 = 2d
7.20 = 2d
3.60 = d <<<<<------- solution for d