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32 votes
32 votes
Exercise 1. A batch of 400 containers for frozen orange juice contains 4 that are defective. Two are selected, at random, without replacement from the batch.

(1) What is the probability that the second one selected is defective given that the first one was defective?

(2) What is the probability that both are defective?

(3) What is the probability that both are non-defective?

User Chris Yin
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1 Answer

16 votes
16 votes

Answer:

1. 1/13,300

2. 1/13,300

3. 2607/2660

Explanation:

Probability is the ratio of the number of possible outcomes to the number of total outcome. The probability that an event will happen added to the probability of the same even not happening is 1.

Given that there are 400 containers of frozen orange juice with 4 that are defective,

non-defective = 400 - 4 = 396

Probability of selecting

Non-defective = 396/400 = 99/100

Defective = 4/100 = 1/100

the probability that the second one selected is defective given that the first one was defective is the same as the probability that both are defective

= 4/400 *3/399

= 1/13,300

the probability that both are non-defective

= 396/400 * 395/399

= 99/100 * 395/399

= 33*79/20*133

= 2607/2660

User MarkeD
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