If x and y are positive integers for which 3x + 2y + xy = 115 + 11x + 2y, then what is x + y?
3x + 2y + xy = 115 + 11x + 2y simplify
8x - xy = - 115
x ( 8 - y) = - 115
x ( y - 8) = 115
factors of 115 = 1 5 23 115
Four possible solutions for x, y
y = 31 x = 5
y = 123 x = 1
y = 13 x = 23
y = 9 x = 115
x + y = 36 or 124
+782 
