Answer B & C are correct because P(A) + P(B) + P(C) add up to 1
Dude I don’t think using this for an exam is it but ok
Y is the function of x so there are two things called Input and output
4b - 7 + 2b + 11 and b + 3 + b + 1 are congruent.
You add the common factors in each problem: 2b + 4 = 2b + 4
The 99.87th percentile, or the area to the left of the 3 standard deviation mark it 99.87% better than everyone/everything else.