How many even 2-digit positive integers less than 80 are there?

Answer 1

There are 80 positive integers from 1 to 80.

Half of them are even, the other half are odd.

So there are 40 even integers from 1 to 80.

2, 4, 6, and 8 have only 1 digit.

All the rest have 2 digits.

So the answer is (40 - 4) = 36 .

However, as the question asked "less than 80" we can not include 80 and so the answer is 35.