Question Detail
Question
Find two positive numbers whose sum is 80 and whose product is maximum
Correct Answer
Option A is the correct answer.
Detailed Explanation
For fixed sum S, the product x(S-x) is maximized when x=S/2. Here 80/2=40, so the numbers are 40 and 40.
Hint
Express the product as a function of one variable, x(80-x), and maximize using calculus.