Suppose you want to build a 1125ft3 swimming pool with a square base of x ft on each side and having y ft depth. If the cost of construction is defined as c = 5x2 + 30 xy, the what values of x amd y will minimize the cost? [M-1.9, IUT : 2021-22]
A 5ft, 15ft
B 5ft, 45ft
C 15ft, 5ft
D None of others
Solution
Correct Answer: Option C