Which graph? Please explain in the comments
What does the work look like first
Answer:
A = choosing a red marble
B = choosing a green marble
Probability of A happening = P(A) = 5/(3+5+4) = 5/12
Probability of B happening = P(B) = 4/(3+5+4) = 4/12
Probability of either happening = P(A) + P(B) = 5/12 + 4/12 = 7/12
The key word in their question is red OR green and that is why we add the two probabilities. If they ask the probability of them both happening (if they said red AND green), you would multiply P(A)*P(B).
<h3>
Answer: Choice 2) sin(B) = cos(90-B)</h3>
Explanation:
The rule is that
sin(A) = cos(B)
if and only if A+B = 90.
Solving for A gets A = 90-B
So we end up with
sin(90-B) = cos(B)
which is the same as
cos(B) = sin(90-B)
