Q. 154.7( 3 Votes )

# In how many ways can 5 red, 3 yellow and 4 green discs be arranged in a row if the discs of the same colour are indistinguishable?

Answer :

Total number of discs= 5 Red + 3 Yellow+ 4 green

n = 12

Since colours are repeating so we use the formula .

Here p_{1}=5 , p_{2}=3, p_{3}= 4

Total ways

= 12× 11× 10× 7× 3

= 27720 ways

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Which of the following are true :

(2 + 3)! = 2! + 3!

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