Please help me with mathematics grade 11

Last year amusement park received 236,758 visitors it was open every day of the year but 7 holliday’s what was the average number of visitors to the park per day

Jeffery conducted a survey in his school and found that 30 of the 50 eighth grade students' favorite subject is mathematics. based on the results, jeffery concluded that out of the 200 students in his school, 120 students' favorite subject is mathematics. select the statement that is true about jeffery's conclusion. a. jeffery's conclusion is not valid because the sample was biased since only 200 students were surveyed. b. jeffery's conclusion is valid because the sample was random since all of the students were eighth grade students. c. jeffery's conclusion is valid because the sample was random. d. jeffery's conclusion is not valid because the sample was biased since all of the students were eighth grade students.

An air conditioning system can circulate 350 cubic feet of air per minute. how many cubic yards of air can it circulate per minute?