Question

A palindrome is a number that reads the same forward and backward. For example, 2442 and 111 are palindromes. If 5-digit palindromes are formed using one or more of the digits 1, 2, and 3, how many such palindromes are possible?

Answer 1

27

Explanation:

Let the 5 digit palindrome formed from 1,2,3,4,5 be represented as XYZXY

Possible outcomes of X are 1,2,3 which give 3 possible outcomes

Possible outcomes of Y are 1,2,3 which also gives 3 possible outcomes

Possible outcomes of Z are 1,2,3 which will give 3 possible outcomes.

The total possible outcome = 3*3*3

= 27