Answer:78 people can attend the party.
Step-by-step explanation:
Given: The formula [tex]c=5p+10[/tex] relates c, the total cost in dollars of hosting a birthday party at a movie theater to p, the number of people attending.
Put c= $400
Then, [tex]400=5p+10[/tex]
[tex]\Rightarrow\ 400-10=5p\\\\\Rightarrow\ 390=5p\\\\\Rightarrow\ p=\dfrac{390}{5}\\\\\Rightarrow\ p= 78[/tex]
i.e. 78 people can attend the party.