A certain business is marketing its product and has determined that, when it raised the selling price of its
product, its sales went down. The number of units
sold, P, is modeled by the equation P=1200-20s,
where s is the selling price, in dollars. Based on this
model, what is the decrease in selling price from 700
units sold to 900 units sold?
a) 5
b) 10
c) 15
d) 20