<p>1.How exactly do you tell when to use the combination formula N!/R!(N-R)! in a problem? In other words, when can you tell whether or not order matters in a problem?</p>
<p>A question like : "How many different committees of three students can be formed from a set of five students?" will use the conmbination formula, but on the other hand, a question such as "In how many different ways can five students be seated in three chairs?" will involve permutations.</p>
<p>Help would be appreciated.</p>
<p>For #1</p>
<p>Take the first equation and move h to one side so you get</p>
<p>h = -hm -m
Then multiply by -1...
-h = hm + m which is the same as
-h = m + mh</p>
<h1>2) Good question...I hate those problems but will be taking Statistics next semester...I'll let ya know then. :)</h1>
<p>Use a combination when you don't CARE about the order</p>
<p>For #1</p>
<p>Take the first equation and move h to one side so you get</p>
<p>h = -hm -m
Then multiply by -1...
-h = hm + m which is the same as
-h = m + mh</p>
<p>Yeah, I see it now..wow I can't believe it took me that long to figure out to move the h..must be a brain lapse :/</p>
<p>Anyway, any ideas on the second problem?</p>
<p>lol hey it took me a full minute before I saw how simple it was...I wanted to do substitutions and a bunch of other stuff, and then it slapped me in the face. Unfortunately, that's how most math problems on tests are for me.</p>
<p>Yeah..the SAT's have a funny way of making you feel pretty dumb after missing a problem and reading a very simple explanation for it.</p>