Permutations And Combinations Question 297

Question: The number of 7 digit numbers which can be formed using the digits 1, 2, 3, 2, 3, 3, 4 is [Pb. CET 1999]

Options:

A) 420

B) 840

C) 2520

D) 5040

Show Answer

Answer:

Correct Answer: A

Solution:

  • Required number = $ \frac{7\ !}{3\ !\ 2\ !}=\frac{5040}{6\times 2}=420 $ . ( $ \because $ 3 is repeated thrice and 2 is repeated twice).