Question

Numbered disks are placed in a box and one disk is selected at random. If there are 6 red discs numbered 1 through 6, and 4 yellow disks numbered 7 through 10, find the probability of selecting a yellow disk, given that the number selected is less than or equal to 3 or greater than or equal to 8.

Answer 1

Answer: The disk selected is one of those 6. Three are red, three are yellow. Therefore, there are 3 chances out of 6 that the disk will be yellow, which reduces to 1/2 or 0.50.

Step-by-step explanation: The short answer is that the numbers given determine the disk, not the fact that two disks are being chosen. There are 6 possible numbers chosen, and half of them will produce a yellow.

The longer answer is that these are not independent events, which would allow one to multiply the probability. The number and the disk are not independent; one determines the other. There is a probability of getting a yellow of 4/10 with the first choice, and then it is 3/9. But the choices are CONDITIONAL upon a certain number's being allowed