First, πr2h = 550 so that h=550/πr2
Surface area of can and base = πr2 + 2πrh and the cost to make the can and base = .02 * this
Surface area of the top = πr2 and the cost to make the top is .08 * this
Substitute the expression for h into the surface area of the can and base.
Then add the two cost expressions to get cost as a function of radius.
Set the derivative of cost = 0 and solve for r.and then get h.
This will be messy!! Good luck.