Answer:
12 boys
Step-by-step explanation:
let [tex]x[/tex] be the number of boys. You can set up an equation using equivalent ratios:
[tex]\frac{4}{7}=\frac{x}{21}[/tex]
Cross-multiply to get:
[tex]7x=84[/tex]
Divide both sides by 7 to get:
[tex]x=12[/tex]
Thus, there are 12 boys at the movie.
Hope this helps :)
