<ol>
<li>During a dance class, each of the twelve students is paired up with each of the other students twice. HOw many total pairings will there be during the class?</li>
</ol>
<p>I was completely lost by the wording of this problem....</p>
<p>it is just 12 students paired up with each other, then times that by two…thus 12 cpr 2 times 2, 132 pairings…</p>
<p>what is CPR?</p>
<p>combination, because you are pairing ppl up, but the actual order of the pairs do not matter, so it isn’t permuation</p>
<p>
</p>
<p>You said you were lost by the wording so here is a breakdown of the question.</p>
<p>
</p>
<p>When approaching a problem like this I highly suggest disregarding “twice” until the end.</p>
<p>Student 1: paired w/ 2,3,4,5,6,7,8,9,10,11,12 (11 total)
Student 2: paired w/ ,3,4,5,6,7,8,9,10,11,12 (10 total) (you omit 1 b.c you already have that pair)</p>
<p>This continues and eventually you get (1+2+3+4+5+6+7+8+9+10+11) = 66.
(66)2 = 132.</p>
<p>Now doing that out every time is boring, tedious, and a huge time waster on the SAT.
Your TI-84 calculator does the same thing when you type 2 * (“12 nCr 2”) = 132.</p>
<p>whattttttttt thats sick avidstudent, remmeber that problem its like 1,2,2,3,3,3. can i use the nCR function for it?</p>
<p>No, that problem has nothing to do w/ probability.</p>