A recipe that serves 8 people requires 1 and one fourth cups of sugar. Using this​ recipe, how many cups of sugar are needed to serve 20 ​people?

Answer 1

8 is proportional to 1 and 1/4

20 is proportional to X

8X = 20 * (1 and 1/4)

8X = 20 * (5/4)

8X = 25

X = 25/8 = 3 and 1/8

Answer 2

let x=no of cups of sugar needed for 20 people

no of cups of sugar needed is proportional to the no of people served

8/20 = 1.25/x

8x = 20*1.25

8x = 25

x = 3.125

3.125 cups of sugar is needed