Assuming that Y is the total income and X is the raised 10 yuan number, there are:

y =( 120-6x)( 160+ 10x)

=-60x^2+240x+ 19200

=-60(x^2-4x+4)+240+ 19200

=-60(x-2)^+ 19440

So we can get: when x=2, the maximum value of y is: 19440 yuan!