Question
Five articles out of which 3 are cups and rest are
glasses have to be arranged on a shelf. Find the number of ways of arrangement in which all three cups are not placed together.Solution
Since there are 5 articles, total number of ways of arrangement = 5! = 120 ways
If we consider 3 cups as one article, therefore, number of ways of arrangement of cups among themselves = 3! = 6 ways
Number of ways of arrangement of remaining three articles = 3! = 6 ways
Therefore, required number of ways = 120 – (6 × 6) = 84 ways
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