SOLUTION: In a shipment of 20 smartphones, 2 are defective. How many ways can a quality control inspector randomly test 5 smartphones, of which 2 are defective?

Question 1132853: In a shipment of 20 smartphones, 2 are defective. How many ways can a quality control inspector randomly test 5 smartphones, of which 2 are defective?

Answer by ikleyn(52781) (Show Source): You can put this solution on YOUR website!
.

The quality control inspector can add 3 randomly selected smartphones from the rest of 20-2 = 18 smartphones.


He can do it by   =  = 816 ways.    


It is the ANSWER to the problem's question.

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On Combinations, see the lessons
    - Introduction to Combinations
    - PROOF of the formula on the number of Combinations
    - Problems on Combinations
    - OVERVIEW of lessons on Permutations and Combinations
in this site.

Also, you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic "Combinatorics: Combinations and permutations".

Save the link to this textbook together with its description

Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson

into your archive and use when it is needed.

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