To begin you would need to find the probability of picking a green sock which would be 3/9; and you could simplify this to 1/3.
After that you need to find the probability of picking a purple sock out of the 8 left, which would provide you with 1/8. To find the probability of both you would multiply 1/8 by 1/3 to find the combined probability which would leave you with 1/24.
