How many 5-digit palindromes contain only even digits?

400

Step-by-step explanation:

There are 400.

Assuming the number must be at least 10,000, then:

In a 5 digit palindrome, the first and last digits must be the same, and the second and fourth digits must be the same; and:

For the first and last digit there is a choice of 4 digits {2, 4, 6, 8};

For each of these there is a choice of 10 digits {0, 1, ..., 9} for the second and fourth digits;

For each of the above choices these is a choice of 10 digits {0, 1, ..., 9} for the third digit;

Making 4 x 10 x 10 = 400 possible even 5 digit palindromes.

$649.60

step-by-step explanation: