Official SAT Study guide question

<p>for everyone who has that blue official sat study guide book, how do i do number 18 on page 476? Also, how do you do other problems that involve “combinations”</p>

<p>someone plz…</p>

<p>See [this</a> thread](<a href=“http://talk.collegeconfidential.com/showthread.php?t=134898]this”>http://talk.collegeconfidential.com/showthread.php?t=134898)</p>