99/ Confidence interval problems

Ineed your ! i was to turn this into pond first thing i gotta do is outline the inside with this plastic how big should i cut the plastic the height: 10 1/2” the length: 40” the width: 12” me !

The mass of a marine organism, in pounds, p years after it is born is given by the polynomial function r(p) = -4p2 + 300p. find the mass when p = 20 years.

Ineed some on this. not sure how to solve.