"susan is consuming 70 grams of protein per day on her 2,000-kilocalorie-per-day diet. what percent of susan's diet is protein? "

The answer to this question would be: 14%
Protein will give a calorie about 4kcal/gram. Then, the total calorie of protein from Susan meal would be: 70 grams * 4kcal/g= 280 kilo calorie.
To find the percentage you will need to divide the total calorie diet with the protein calorie. The calculation would be:

protein percentage= protein calorie/ total calorie 
protein percentage= 280kcal / 2,000kcal = 14%