Proportion and Fraction

Question

The nutrition information on a bran cereal box says that a 1/3 cup serving provides 80 calories and 8 grams of dietary fibre. At the rate, how many calories and grams of fibre are in a 1/2 cup serving?

Answer 1

1/3 1/2 1/3 1/2

----- = ------ and --------- = --------------

80 c 8 f

cross multiplies:

1/3 * c = 80 * 1/2 and 1/3 * f = 8 * 1/2

1/3 * c = 40 and 1/3 * f = 4

c = 40*3 = 120 and f = 4*3 = 12

120 calories and 12 grams of dietary fiber

? = 40 * 3 and ? =