Looking at this problem in terms of geometry makes it easier than trying to think of it algebraically.
If you want the largest possible x+y, it's equivalent to finding a rectangle with width x and length y that has the largest perimeter.
If you want the smallest possible x+y, it's equivalent to finding the rectangle with the smallest perimeter.
However, the area x*y must be constant and = 100.
We know that a square has the smallest perimeter to area ratio. This means that the smallest perimeter rectangle with area 100 is a square with side length 10. For this square, x+y = 20.
We also know that the further the rectangle stretches, the larger its perimeter to area ratio becomes. This means that a rectangle with side lengths 100 and 1 with an area of 100 has the largest perimeter. For this rectangle, x+y = 101.
So, the difference between the max and min values of x+y = 101 - 20 = 81.
4 servings : 2 potatoes and 4 celery sticks. Find the number of potatoes and celery sticks in 6 servings. 6/4 = 1.50 2 potatoes x 1.50 = 3 potatoes 4 celery sticks x 1.50 = 6 celery sticks 6 servings of stew has 3 potatoes and 6 celery sticks. Other way of computing for the 6 servings is getting the number of potatoes and celery sticks per serving.
