Question

A sports store sells 70 pairs of running shoes per

day for $40.00 each. The owner estimates that
for each $3.00 increase in price, 3 fewer sales
are made each day. What price should be charged
to maximize profit?

Answer 1

$55

Explanation:

so, we know that each day the store will currently sell $2800 worth of shoes.

we want to know the maximum of the expression (40+3x)(70-3x), expanding we get 2800 - 9x^2 + 90x,

the maximum of this would be x = 5, so the price they should charge is 55