He made 3.75 gallons. There was 1/10 remaining, meaning each tenth was 6 cups. The entire thing is 10 tenths so you do 6(10) to get 60 cups. After converting to gallons by doing 60÷26, you get 3.75.
Original price:
6(3.5)
21
New Price:
1.15(21)
24.15
24.15-21
$3.15 more
Yes, the variable of interest is two-dimensional.
If you are making a graph about the area of a country, that is a two dimensional measurement. It would be ok to make a graph that is also 2 dimensional.
