In a lot of 12 Microwave ovens, there are 3 defective units. A person has ordered 4 of these units and since each is identically packed, the selection will be random. What is the probability that
i. all 4 units are good.
ii. Exactly 3 units are good,
iii. at least 2 units are good.

Explanation

Given that there are 12 microwave ovens i.e., `n=12`

in that `3` are defective

then number of good units =`9`

The probability of good unit is
=`9/12
`

=`0.75`


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