<p>Hey guys, I'm wondering if anyone can give me a quick review on when to use nPr and nCr. I remember there was a question that was like there are 4 different colored cakes, how many different 3-colored combinations can be made? Or something, idk I forgot. </p>
<p>And any tips for the last two questions on each section? Trying to get a 700+ this time.</p>