The numbered disks shown are placed in a box and one disk is selected at random. Find the probability of selecting an even number, given that a green disk is selected. Find the probability of selecting an even number, given that a green disk is selected. (Type an integer or a simplified fraction.)

Step 1 ：The problem is asking for the conditional probability of selecting an even number given that a green disk is selected.

Step 2 ：To solve this, we need to know the total number of green disks and the number of green disks that are even.

Step 3 ：The total number of green disks is 5 and the number of green disks that are even is 2.

Step 4 ：The probability of selecting an even number, given that a green disk is selected is calculated as the ratio of even green disks to total green disks.

Step 5 ：Using the formula for conditional probability, we get \(\frac{2}{5} = 0.4\)

Step 6 ：Final Answer: The probability of selecting an even number, given that a green disk is selected is \(\boxed{0.4}\).