<p>The question reads:
How many different sets of two parallel edges are there in a cube?
also, any general advice for these types of questions? They always give me some trouble.
Thanks</p>
<p>I would think 12? if you separate the cube into 2 sets of 4 parallel lines you can get 6 pairs for each set. Combinations (4x3)/(2x1) I’m pretty sure that’s right, not sure about any advice, since I haven’t taken any SAT Subject tests before</p>
<p>I also thought 12 but answer is 18.</p>
<p>oh wow I forgot there are three sets rofl… there are 12 lines 3 groups of 4 not 8, 2 groups of 4…wow I failed, 3x6…</p>
<p>Each face has 4 edges, and each edge (not over counting) can be parallel to 1 other edge, so that’s 4 x 6 or 24 lines. But then opposite edges can also be parallel, opposite as in not touching the same face, so thats 12 more, so a total of 36 parallel edges, and so 18 pairs.</p>