Based on the given information, each shelf can hold 9 books. (27/3 = 9) That means 2 additional shelves will hold 18 books. Add 18 to 36 to find the total, which is 54.
Hope that helped you.
ANSWER
D) sin Y
EXPLANATION
The given triangle is a right triangle.
This implies that that:

Then we have

Recall that

But

When we do the substitution, we get,

Therefore cos(x) is a equivalent to sin(y).
The correct answer is D.
Answer:
Step-by-step explanation:
um i no but i can not tell u
Answer:
Step-by-step explanation:
This is a Combination (as in permutation vs combination) question the symbol (n r) refers to "n choose r". This is sometimes written as nCr
i.e the question is asking you to find how many combinations each will yield when you chose r items from n item without repetition and order does not matter.
I will only do the first question for you and you can just follow the same steps to solve the rest of the questions.
Recall that

Consider question a) we are given (5 1) or ₅C₁
we can see that n = 5 and r = 1
If we substitute this into the formula:
₅C₁ = (5!) / [ (1!)(5- 1)!]
= (5!) / [ (5- 1)!]
= (5!) / (4!)
= (5·4·3·2·1) / (4·3·2·1)
= 5
hence ₅C₁ = 5