I'm having a problem with probability. someone asap.

a first grade class of nine girls and seven boys walks into a class in alphabetical order (by last name). what is the probability that three girls are the first to enter the room? show your calculation.

(a) 0.15
(b) 0.20
(c) 0.35
(d) 0.45,

The jurassic zoo charges $14 for each adult admission and $5 for each child. the total bill for 77 people from a school trip was $565. how many adults and how many children went to the zoo? i

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.

What is the value of the expression below? (81^2)^1/8