armaan700+ wrote:There are 3 red chips and 2 blue ones.
When arranged in a row, they form a certain color pattern, for example RBRRB. How many color patterns?

10
12
24
60
100

The number of possible patterns is 5! / (3!*2!) = (5 x 4) / 2 = 10.

Alternate Solution:

Note that if the 5 chips were all of different colors, then we would have 5! = 120 different arrangements. But because there are 3 identical red chips and 2 identical blue chips, we must reduce the number of possible arrangements, using the indistinguishable permutations formula, obtaining 5! / (3!*2!) = (5x4) / (2x1) = 10.

Answer: A