Question

Greg is a software salesman. His monthly salary is $1700 plus an additional $80 for every copy of Math is Fun he sells. Let S represent his total salary this month (in dollars), and let N represent the number of copies of Math id Fun he sells. Write an equation relating S and N, and then graph your equation using the axes below.

Answer 1

» Assume it is a direct proportionality:

`{ \rm{N \: \alpha \: \: S}}`

» Fomulate the equation:

`{ \rm{N = kS}}`

» When N is 1, S is $1700 + 80

`{ \rm{1 = k(1700 + 80)}} \\ { \tt{k = (1)/(1780) }}`

» Equation becomes:

`{ \rm{N = (S)/(1780) }} \\ \\ { \boxed{ \rm{ \red{ \:S = 1780N }}}}`

»