at Initech, 50% of all employees surf the Internet during work hours. 20% of the employees surf the Internet and play solitaire during work hours. It is also known that 60% of the employees either...

at Initech, 50% of all employees surf the Internet during work hours. 20% of the employees surf the Internet and play solitaire during work hours. It is also known that 60% of the employees either surf the Internet or play solitaire (or both) during work hours.
a) what proportion of the employees pla...