How many gallons of fuel costing $1.15 a gallon must be mixed with a fuel costing $0.85 per gallon to get 40 gallons of a fuel that costs $1 per gallon? Formulate an equation and then solve it in order to determine how many gallons of fuel costing $1.15. Show all of your work.

Let x = the required number of gallons of fuel $1.15 per gallon.

From the problem description, you can write:

x ($1.15) + 20 ($0.85) = (20+x) ($1.00) Simplify and solve for x.

1.15x+17 = 20+x Subtract x from both sides.

0.15x+17 = 20 Subtract 17 from both sides.

0.15x = 3 Finally, divide both sides by 0.15

x = 20

You would need to add 20 gallons of fuel $1.15 per gallon to 20 gallons of fuel $0.85 per gallon to obtain 40 gallons of fuel $1.00 per gallon.

This might not be correct but I hope it will be useful to you : 3