Posted by steveo on Saturday, August 30, 2008 at 4:14pm.
You'll need to fill in the following table with numbers that add up to 900, because your Venn diagram is going to be composed of these seven mutually exclusive segments:
Female / Non-Union / Non-Single
Union / Non-Female / Non-Single
Single / Non-Union / Non-Female
Female / Union / Non-Single
Female / Single / Non-Union
Union / Single / Non-Female
Female / Union / Single (120)
Your Venn diagram is composed of three mutually overlapping circles, of which the only segment for which you know the number of employees is the middle one: all the other information you have so far relates to two or more adjacent segments - so you've got to break them up into their individual components.
Start in the middle of the diagram with the 120 Female/Union/Single employees, and work outwards. For example, the 190 Female/Union members include 120 who are Female/Union/Single, so the number of Female/Union/Non-Single employees is 190 - 120 = 70. The number of Single/Union employees is 187, so the number of Single/Union/Non-Female employees is 187 - 120 = 67. Carry on like this, filling in both the table above and the relevant segments of the diagram as you go, until you've completed the whole diagram.