Answer:
130 people
Explanation:
This is a classic ratio problem that can be solved through dimensional analysis (the use of units and a little bit of thinking). If the ratio of people to pizzas for a party is 13/3, or in otherwords, for every 13 people there exists 3 pizzas, then if you have 30 pizzas, there will be 130 people, because
30 pizzas · 13/3 (peoples per pizzas)=130 people