Number of people who live under the age of 18 = 3360
Step-by-step explanation:
Total population = 16,000
Percentage of people under the age of 18 = 21%
Number of people who live under the age of 18 = Total population × Percentage of people under the age of 18
Number of people who live under the age of 18 = 16000 × 21%
= 16000 × 0.21
Number of people who live under the age of 18 = 3360