<p>SECTION 6:</p>
<p>17.) Shouldn't the answer to this one be 989 instead of 149? Here is my logic behind this:</p>
<p>10 clocks chime "n" times on the "nth" hour. It is the 8th hour, so it would be 10x8x8=640.
10 clocks chime once on the half hour, so 2x10=20.
5 clocks chime "n" times on the "nth" hour. It is the 8th hour, so it would be 5x8x8=320.
3 clocks chime once on the hour. 3x1=3.
3 clocks cime once on the half hour, so 3x2=6.</p>
<p>So, 640+20+320+3+6=989. Why would it be 149 if it says the clocks chime "N" TIMES on the "NTH" hour?</p>
<p>18.) I understand that this is a permutation, but do math questions like this usually appear on the SAT....?</p>
<p>Hi,</p>
<p>Section 6 #17:
I think you’re misunderstanding the question. </p>
<p>A clock chimes n times on the nth hour simply means that if it’s 8 o’clock now, the clock will chime 8 times. If it’s 9 o’clock, the clock will chime 9 times. It doesn’t mean that if it’s 8 o’clock, the clock will chime 8 x 8 times (just think about it, is it even logical in the first place for a clock to chime 64 times?)</p>
<p>So 10 Type A clocks chime 8x10 = 80 times on the 8th hour, while 5 Type B clocks chime 8x5 = 40 times on the 8th hour. Total = 80 + 20 + 40 + 3 + 6 = 149.</p>
<h1>18: I have seen permutation and combinations questions quite a few times on the SAT, but they’re usually of the kind “There are 3 different sizes and 5 different colours of shoes on sale. How many different combinations of colours and sizes can you choose?”</h1>
<p>Essentially the concept is still the same, so I’d advice you take time to understand what the question is asking for and how to do it (:</p>