They paid $720
Here's why:
The formula to this is Interest = Principal x Rate x Time or i = prt
Principal = $2000
Rate = 12%
Time = 3 years
2000 x .12 x 3 = i PEMDAS
2000 x .12 = 240
240 x 3 = 720
i = $720
Y=10x-40
i hope that helps!!
You can write this ratio in two other ways:
7 to 13
7 : 13