The local amusement park is a popular field trip destination. This year the senior class at high school a and the senior class at high school b both planned trips there. The senior class at high school a rented and filled 12 vans and 1 bus with 211 students. High school b filled 11vans and 9 buses with 541 students. Every van had the same number of student in it as did the buses. How many students can a van carry? How many students can a bus carry?