Answer:
[tex]1,500\ people[/tex]
Step-by-step explanation:
we know that
There are [tex]4,500[/tex] people in Springfield. [tex]1/3[/tex] of the population of Springfield are under the age of [tex]21[/tex]
so
To calculate how many people are under [tex]21[/tex] in Springfield
Multiply [tex]4,500[/tex] by [tex]1/3[/tex]
[tex]4,500*(1/3)=1,500\ people[/tex]