Q21

[AndreaO452]

Can someone please show me why O is placed higher than M?

[Misti Duvall]

Sure! The short answer is because of numeric distribution. Here we know the total number of elements (8), but not how many are in each group (we only know it's at least 2). Since the first rule says more are on the bottom group than the top group, we also know the bottom must have at least 3. So the only possible numeric distributions are 2.2.4 (in which case the 4 must be the bottom group) and 2.3.3 (in which case the 2 must be the top group).

If we test answer choice (A) by trying to make O not on a higher shelf than M, the only option is to put them both on the middle shelf, since M can't be on the top and O can't be on the bottom. That looks like this:

T: K __
M: I O F M
B: L __ __

Meaning the middle group has four, which won't work. So O has to be on a higher shelf than M.

Hope this helps.