A high school is hosting a blood drive. The sign-up sheet has 5 slots available for Mr. Bentley’s class and 6 slots available for Ms. Curren’s class. If there are 21 students in Mr. Bentley’s class and 23 students in Ms. Curren’s class, which expression represents the number of possible groups of students that can fill the 11 available slots?

Me with this assignment ! i only partially understand, so explain. also it's a work sample. at the championship bike race, steve and paula were fighting for first place. steve was 175 feet ahead of paula and had only 300 feet left to go. he was very tired and was going only 9 feet per second. paula was desperate to catch up and was going 15 feet per second. who won the bike race and by how far did she/he win?