PT5.S3.Q12 - The number of North American children who are obese

sabrinarielle

Can anyone explain why this is C? thank you for the help!

Admin Note: Edited title. Please use the format: "PT#.S#.Q# - brief description of the question"

Ashley2018-1

If there are 100 people and 15 of them are obese, that means they have a higher percentage of body fat compared with 85 percent of their peers (85 people). If that number were increased, and now 150 of them are obese, in order to maintain that percentage (obese means to have more fat than 85% of people), then there needs to be 850 non-obese people.

leoxnardx

This question is basically a number game. So we know that the definition of obesity here is not absolute or about BMI; it's relative, and only those who are more obese than the 85% are classified as obese. So lets say there are 1000 children. The 150 who are more obese than the 850 will be classified as obese.

According to the question stem, the amount of obese children increased steadily in the past 4 years. Let's just say we now have 500 officially obese children after four years. Now, the standard still haven't change: only the fattest 15% will be classified as obese. so that means that the 500 officially declared obese children are still the 15% who are fatter than the rest of the 85% of children. Therefore, the total number of the children increased to 500/15%, which is 3333 children. Thus, from this we know that the total amount of children has to increase for us to have a steady increase of obese kids.