Answer:
probability = 0.008
probability = 0.0256
Explanation:
we know here probability of defective is 0.2
so probability of not defective is 1 - 0.2 = 0.8
as we know 3 item is arrive off process line in succession
so The probability that an item is defective is
as P(defective) = 0.20
as all item are independent so
probability that all three items are defective is
probability = 0.20 × 0.20 × 0.20 = 0.008
and
probability that exactly 3 of next 4 are defective
so number of way that can choose 3 out of 4 is
=
= 4
so as all are independent probability is
probability = ( the number of way to choose 3 out of 4 ) × ( 3 item defective ) × ( 1 item not defective )
probability = × 0.2³ × ( 1- 0.2)
probability = 4 × 0.008 × 0.8
probability = 0.0256