Hello! I had some trouble doing this Quant practice problem and I thought this would be a simple 3 options, {2}, {2,4}, {2,4,6}. for subsets with only even elements. But then Greg mentions there’s this trick where you multiply 2^3. I don’t understand where this comes from? Could someone explain where the 2 and 3 come from and why we do this in this problem? Thank you.
You’re missing \{4\}, \{6\}, \{2,6\}, and \{4, 6\}.
That’s the total number of subsets you can form from any 3-element set (the 3 elements here are 2,4, and 6). We subtract 1 because the previous calculation also counts the empty set as a subset.