How many even 2-digit positive integers can be written using the numbers 2, 4, 5, and 8?

12

Step-by-step explanation:

To have an even integer the number's endian has to be an even number. Consider the 2-digit positive number like _ _ and place the number of possible options out of four total options in each blank space. We have 3 even options, so we can fill the endian blank like this _ 3

Since the first digit can be any number, therefor, we have 4 options for the first blank space 4 3. Just multiply the two numbers and you have the answer.

22, 24, 28, 42, 44, 48, 52, 54, 58, 82, 84, 88