<p>pg 597 #15</p>
<p>diagram problem</p>
<p>pg 598 #18</p>
<p>@ | X | __ | * | o |</p>
<p>If the 5 cards shown above are placed in a row so that __ is never at either end, how many different arrangements are possible? answer is 72</p>
<p><a href=“http://talk.collegeconfidential.com/sat-preparation/788653-help-offcial-sat-guide-math-problem.html[/url]”>http://talk.collegeconfidential.com/sat-preparation/788653-help-offcial-sat-guide-math-problem.html</a></p>
<p>4 possibilities for one end.</p>
<p>then 3 possibilities for the other end.</p>
<p>then 3, 2, 1 for the middle.</p>
<p>4x3x3x2x1</p>
<p>pg.597 #15</p>
<p>QS/QV = 1/3</p>
<p>that means the length of QS is 1
and the entire length of QV is 3
(Obviously)
so using that we can determine that the length of SV by itself is 2</p>
<p>2nd part: PT /PR = 3/4</p>
<p>that means PT = 3 and PR = 4
(Again obviously)</p>
<p>so we need to find the value of the fraction area PST /area PQR</p>
<p>area of a triangle = bh 1/2</p>
<p>first lets find the area of PST.</p>
<p>the base is 3 as we determined line PT is 3. the height of SV is 2 as we determined above.
(3 x 2) x 1/2 = 3
thus the area of PST = 3</p>
<p>now let’s find the area of PQR.</p>
<p>base or length PR = 4 as stated in the original question
height or length QV = 3 as stated in the original question.
(4x3) x 1/2 = 6</p>
<p>so area PST / area PQR </p>
<p>= 3/6
= 1/2…or 0.5</p>