Approximately how many 15-19-year-old males were there in China in 2010?

• A. 56 million
• B. 28 million
• C. 84 million
• D. 112 million

Answer: (A)

This question hinges on how many people are in a specific age-and-sex group, which comes from births in the past and how many survived to that age. For a 5-year band like 15–19, the size mainly tracks how many babies were born roughly 15–19 years earlier, adjusted for mortality, with males typically a bit more numerous than females at birth and carrying through adolescence.

In 2010, the total number of people in the 15–19 range in China was a bit over 100 million. Since males make up a little more than half of that age group, the number of 15–19-year-old males is about 55–60 million. So 56 million is the closest estimate.

The other options don’t fit as well: they either imply a much smaller or much larger cohort than the known size of the 15–19 population, or don’t account for the slight male excess in this age range.