A Boy Scout troop plans to sell bags of popcorn to raise money for a camping trip. To determine the number of bags they should order, they randomly survey 60 people and asked which flavor of popcorn they prefer. If the troop is ordering 500 bags of popcorn, how many should be plain based on this survey? There are 9 plain bags, 24 butter bags, 12 cheese bags and 15 caramel