Answer:
a=9
divide 81 by 9 on both sides and you get 9.
Step-by-step explanation:
Answer:
We use Baye's theorem: P(A)P(B|A) = P(B)P(A|B)
with (A) being defective and
(B) marked as defective
we have to find P(B) = P(A).P(B|A) + P(¬A)P(B|¬A). .......eq(2)
Since P(A) = 0.1 and P(B|A)=0.9,
P(¬A) = 1 - P(A) = 1 - 0.1 = 0.9
and
P(B|A¬) = 1 - P(¬B|¬A) = 1 - 0.85 = 0.15
put these values in eq(2)
P(B) = (0.1 × 0.9) + (0.9 × 0.15)
= 0.225 put this in eq(1) and solve for P(B)
P(B) = 0.4
A. is the correct answer, because you are adding the same numbers as shown in the expression above, however, in a different order
