If they exist, find two numbers whose sum is 100and whose product is a minimum. If such two numbers do not exist, explain why.

1 Answer

jeew-m's profile pic

jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted on

Let A and B are the numbers which satisfy this criteria.

Then (A+B) = 100

If the product is P then;

P = A*B = A*(100-A) = 100A-A^2


Let consider (50-A)^2;

(50-A)^2 = 2500-2*50*A+A^2

(50-A)^2 = 2500-(100A-A^2)

(100A-A^2) = (50-A)^2-2500

               P = -(50-A)^2+2500


(50-A)^2 is always >=0

So the function P is gradually decreasing.

When A=50 then P gives its maximum.

So there is no minmum to the product of the numbers.

When A=50 then B=50

No two numbers only one number satisfy the criterian even we have a maximum value.