The solution for this problem is:
Let x be the number of months; and
Let y be the amount paid
We know that m is $199 per month and the two other given are 6 months and 2694.
y = 199 (x -6) + 2694
y = 199 (36 -6) + 2694
y = 199 (30) + 2694
y = 8664
Mr. Scott paid $8664 after 3 years.