Answer:
The area 2730 possible arrangements of first, second, and third place.
Step-by-step explanation:
The order in which the students finish is important. For example A, B and C is a different finishing order(outcome) than B, A and C. So we use the permutations formula to solve this question.
Permutations formula:
The number of possible permutations of x elements from a set of n elements is given by the following formula:

In this question:
3 from a set of 15. So

The area 2730 possible arrangements of first, second, and third place.
Answer:
D
Step-by-step explanation:
Let z = sin(x).
.. z^2 -2z = 2
.. z^2 -2z +1 = 3
.. (z -1)² = 3
.. z -1 = ±√3
.. z = 1 -√3 . . . . . the positive solution is extraneous
sin(x) = 1 -√3