Mr. katz's science class is planning a field trip. thirty people are going on the trip. there are 7 drivers and two types of vehicles, vans and cars. each van seats 6 people, including the driver, and each car seats 4 people, including a driver. if there are no extra seats in any of the vehicles, how many vans are taken?

Over the course of the school year, you keep track of how much snow falls on a given day and whether it was a snow day. your data indicates that of twenty-one days with less than three inches of snow, five were snow days, while of the eight days with more than three inches of snow, six were snow days. if all you know about a day is that it is snowing, what is the probability that it will be a snow day?