Answer:
a) Therefore, the probability is P=1/52.
b) Therefore, the probability is P=9/400.
Step-by-step explanation:
We know that a batch of 40 parts contains six defects.
a) We calculate the probability that the both parts are defective, if two parts are drawn randomly one at a time without replacement.
The probability for the first is 6/40.
The probability for the second is 5/39.
We get:
Therefore, the probability is P=1/52.
b) We calculate the probability that the both parts are defective, if two parts are drawn randomly one at a time with replacement.
The probability for the first is 6/40.
The probability for the second is 6/40.
We get:
Therefore, the probability is P=9/400.