Answer:
54%
Step-by-step explanation:
total students are 50
20+7 scored at least 81 = 27
27/50=54%
the answer is the litter B
Answer:
0.7
Step-by-step explanation:
Probability of defective = 0.7
P(non-defective) = 1 - 0.7 = 0.3
Let X be the trial at which we get the first non-defective
Then X follows a geometric distribution.
X ~ Geo (0.3)
What has happened already will not affect the probability.
P(atleast 2 more) = P(X > 1)
= 1 - P(X = 1)
= 1 - (0.3)
= 0.7