Answer:
$7.
Step-by-step explanation:
We have been given that Lani's mother gave her and her two sisters $21 to spend at the movies.
We are asked to find the amount each girl have to spend.
To solve our given problem, we will divide $21 with 3 as Lani and her two sisters would be 3 persons.
[tex]\text{Amount that each girl have to spend}=\frac{\$21}{1+2}[/tex]
[tex]\text{Amount that each girl have to spend}=\frac{\$21}{3}[/tex]
[tex]\text{Amount that each girl have to spend}=\$7[/tex]
Therefore, each girl gets $7 to spend.
