Question

How many 4 digits even numbers are possible from digits 1 to 9 if repetition is allowed?

(a) 6561

(b) 2016

(c) 1344

(d) 2916

I have been asked this question in an interview for internship.

The query is from Fundamental Principle of Counting topic in division Permutations and Combinations of Mathematics – Class 11

Answer 1

The correct choice is (d) 2916

The best explanation: Total digits are 1-9 i.e.9. Even number means 2,4,6,8 at unit’s place.

So, 4 possible digits for unit place. Rest all positions are filled in 9 ways.

Hence, by the fundamental principle of counting, total possible numbers are 9*9*9*4 = 2916.