Hello all(adsbygoogle = window.adsbygoogle || []).push({});

Set X has x elements and Sset Y has y elements and Set Z consists of all elements are are in either set X or set Y with the exception of the k common elements. I know that the answer is

x+ y - 2k, however how would I get this? Should I just use a practical example?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Set Theory Question

**Physics Forums | Science Articles, Homework Help, Discussion**