Numbered disks are placed in a box and one disk is selected at random. If there are 4 red discs numbered 1 through 4, and 2 yellow disks numbered 5 through 6, find the probability of selecting a red disk, given that an odd-numbered disk is selected.

0.66 = 66%

Step-by-step explanation:

If we know that a odd-numbered disk is selected, we know that the number is 1, 3 or 5.

So, if it is a red disk, is can be number 1 or 3, so we have two possibilities.

If it is a yellow disk, it needs to be number 5, so we have just one possibility.

We have a total of 3 possibilities, and 2 of them are with red disks, so the probability is 2/3 = 0.66 = 66%