The demand for your hand-made skateboards, in weekly sales, is

q = −4p + 600
if the selling price is $p. You are prepared to supply
q = 6p − 400
per week at the price $p. What price should you sell your skateboards for so that there is neither a shortage nor a surplus?

well, just set demand = supply and solve for p.

To find the price at which there is neither a shortage nor a surplus, we need to find the price at which the demand is equal to the supply.

First, let's set the demand and supply equations equal to each other:

-4p + 600 = 6p - 400

Now, let's solve for p to find the price:

-4p - 6p = -400 - 600
-10p = -1000
p = -1000 / -10
p = 100

Therefore, the price at which there is neither a shortage nor a surplus is $100.