The question is in the photo, that answer is not correct. At least I do not know if it is.

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.

The distance between two cities is 368 miles. if the scale on the map is 1/4 inch=23 miles, what is the distance between the cities on the map?

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle