First lets figure out the costs
500+300 +5x where x is the number of pencils
800 +5x
Costs
C(x) = 800+5x
I would chooses 8 for the price of a pencil. No student would pay 50 dollars for a pencil
To break even
8x = 800+5x
Subtract 5x from each side
8x - 5x = 800+5x-5x
3x = 800
Divide each side by 3
3x/3 = 800/3
x = 266.67
We would need to sell at least 267 pencils to break even
To increase their profit, they could increase the selling price of the pencils. They could do more advertising of their pencils to sell more pencils.