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suppose that 9 good fuses and 4 defective ones have been mixed up. to find the defective fuses, we test them one-by-one, at random. what is the probability that we are lucky and find both of the defective fuses in the first two tests? (5 points) 1). with replacement 2). without replacement

Sagot :

The probability that we are lucky and find both of the defective fuses in the first two tests with replacement is 1/13 and without replacement is 12/169.

In the given question, 9 good fuses and 4 defective ones have been mixed up.

To find the defective fuses, we test them one-by-one, at random.

We have to find the probability that we are lucky and find both of the defective fuses in the first two tests.

1). with replacement

2). without replacement

There are 9 good fuses and 4 defective ones.

So the total number of defective fuses = 9+4 = 13

Now the probability first test will find a defective is 4/13

Without replacement, 2nd will find another defective with probability = 3/12.  

Probability of finding 2 defectives on 1st two tests is

P(R) = 4/13 x 3/12

P(R) = 12/156

P(R) = 1/13

Now the with replacement the probability is

P(E) = 4/13 x 3/13

P(E) = 12/169

The probability that we are lucky and find both of the defective fuses in the first two tests with replacement is 1/13 and without replacement is 12/169.

To learn more about probability link is here

brainly.com/question/11034287

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