How do I answer this word math problem

Question

The nutrition information on the cereal box says that a 1/2 cup
serving provides 120 calories and 6
grams of dietary fiber. At that rate, find how many calories and grams of fiber are in a 2/3 cup
serving?

Answer 1

For the calories:

 

120 : 1/2 :: c : 2/3        proportion

80 = c/2                       product means/extremes

160 = c

 

For the fiber:

6 : 1/2 :: f : 2/3

4 = f/2

8 = f