Permutations And Combinations Question 289

Question: All possible four digit numbers are formed using the digits 0, 1, 2, 3 so that no number has repeated digits. The number of even numbers among them is

Options:

A) 9

B) 18

C) 10

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

  • In forming even numbers, the position on the right can be filled either 0 or 2. When 0 is filled, the remaining positions can be filled in $ 3\ ! $ ways and when 2 is filled, the position on the left can be filled in 2 ways (0 cannot be used) and the middle two positions in $ 2\ ! $ ways (0 can be used). Therefore the number of even numbers formed $ =3\ !+2(2\ !)=10 $ .