Supposed a firm conducted a survey of workers involving the variable ‘’skill’’ and ‘educational level’. The survey revealed that 50% of the workers are elementary school graduate (E), 40% are...

Supposed a firm conducted a survey of workers involving the variable ‘’skill’’ and ‘educational level’. The survey revealed that 50% of the workers are elementary school graduate (E), 40% are secondary school Graduates (S) and 10% are college and above Graduates (C). If on the basis of skill, the survey revealed that 10% of Elementary school Graduate are unskilled, 5% of secondary school Graduate are unskilled, and 2% of college and above Graduates are unskilled.

Suppose a worker is selected randomly and is found to be unskilled. What is the probability that the worker is a College Graduate?