A salesman has a base salary of $28,000 and earns in a addition 5% commission per unit for the first 100 units sold, 7.5% per unit for the next 100 units sold and 12% per unit for any additional units sold (ie; above 200)

a) if the market price per unit is $7500, give the function of the income earned in terms of units sold

b) What is the salesman’s income if he sells 338 units?

c) How many units must he sell to have an income of at least $35; 000:00?