Among all pairs of numbers (x, y) ( x , y ) such that 4x+y=18 4 x + y = 18 , find the pair for which the sum of squares, x2+y2 x 2 + y 2 , is minimum. write your answers as fractions reduced to lowest terms.

Damon makes 20 cups of lemonade by mixing lemon juice and water. the ratio of lemon juice to water is shown in the tape diagram. lemon juice\text{lemon juice} lemon juice water\text{water} water how much lemon juice did damon use in the lemonade? cups