Which set of values is a function? (9,5) (10,5) (9,-5) (10,-5)
(6,-5) (7, -3) (8, -1) (9, 1)
(2, -2) (5, 9) (5, -7) (1, 4)
(3,4) (4,-3) (7,4) (3, 8)

Compare these two waves: the blue and orange waves have the same pitch, but the blue wave is louder. the blue and orange waves have the same volume, but the blue wave has a higher pitch. the orange wave has a higher pitch, but the blue wave is louder. the blue wave has a higher pitch, but the orange wave is louder.

Which one ? is the answer and how to find this answer

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?