How many even positive integers less than 300 can be written using the number 2 4 5 and 8?

18

Step-by-step explanation:

Let us first tackle 2-digit numbers.

They are 24, 25, 28, 42, 45, 48, 52, 54, 58, 82, 84, and 85. That makes 12 2-digit numbers.

Now for the 3-digit numbers:

245, 248, 254, 258, 284, and 285. That makes 6 3-digit numbers.

Therefore, there are 12 + 6 = 18 numbers under 300 that can be made using these numbers.