Answer: $26
Step-by-step explanation:
Let the number of $2 price increases be x.
This means that if the price is 10+2x, 42-2x shoes are sold.
So, the revenue is (10+2x)(42-2x).
To maximize profit, we must maximize revenue.
[tex](10+2x)(42-2x)\\\\=-4x^2 +64x+420[/tex]
The maximum is at [tex]x=-\frac{64}{2(-4)}=8[/tex], so the price should be 10+2(8)=$26.
