Permutations And Combinations Question 295

Question: How many numbers greater than 24000 can be formed by using digits 1, 2, 3, 4, 5 when no digit is repeated [RPET 1999]

Options:

A) 36

B) 60

C) 84

D) 120

Show Answer

Answer:

Correct Answer: C

Solution:

  • The digits are 1, 2, 3, 4, 5. We have to form number greater than 24000. Required number will be = (Total) - (Those beginning with 1) - (Those beginning with 21) - (Those beginning with 23) = $ 5!-4!-3!-3!=120-24-6-6=84 $ .