I know you got it wrong and you obviously did it a while ago but the correct answer was C = 22.44.
Cost of 7 gallons=$24.50
Cost of 1 gallon=24.50/7=3.5
Cost of 15 gallons=15*3.5=52.5
Cost of 15 gallons will be $52.5
The answer is in the image
The total nom of code that can be used is equal to 5+3 = 8
The solution is in the following image
y=2x+15
where y=Value of coin
x=Age in years
Value of coin after 19 years=2*19+15
=$53
Therefore, Value after 19 years=$53
The answer is in the image
It will provide an instant answer!