The manager of a company uses the function shown to model its profit based on the price of a product in dollars, x.

f(x) = (x - 2)(53 - x)
​

A total of 300 children and adults attended a school play.  There were 21 times as many children in attendance as there
were adults.

This situation is modeled by the given system of equations, where a represents the number of adults and c represents the
number of children.

c = 21a
a + c = 330

How many children attended the play?