I think the correct answer from the choices listed above is the second option. Combining probabilities is a function of mutually exclusive events. Joint probability<span> is a measure of two events happening at the same time, and can only be applied to situations where more than one observation can be occurred at the same time.</span>
Answer: x=1 y=3....do you need to show your work?
Required probability = number of grade B' s in science / total
grades in science class
= 0.320
The is a because Y = x is 21 and 544 is 21
Answer: Fernando has 29 books
Step-by-step explanation:
The prime numbers between 21 and 30 are 23 and 29.
hence, the possible number of books Fernando has 23 or 29.
After taking 4 books away, the total number of books left can be :-
23-4=19
Since, 19 is not a square number so he cannot be able to place the same number of books on each shelf of his bookcase.
So Fernado doesn't have 23 books.
29-4=25
Also, 
Here, 25 is a square number so he will be able to place the same number of books on each shelf of his bookcase.
Therefore, Fernando has 29 books.