How to do these 2 Math problems?

Test Preparation SAT Preparation
1

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<a href="http://i%5B/url%5D"&gt;http://i&lt;/a>. imgur. com/RXEDtpi.png</p>

2

<p>Answers are 80/3/26.6/26.7, and 101, respectively</p>

3

<p>for the 1st qs
since the car travelled 10 miles with a speed of 20m/h, so the car travelled exactly half an hour.
Likewise, for the second 10 miles, the car travelled 1/4 hour, which is 15 minutes.</p>

<p>So in general, the car travelled 20 miles in 1/2+1/4 hour
so we know the speed is 20/0.75 = 80/3</p>

<p>For the 2nd question
the fence actually is the flap places at both sides of the stretch. So you know that there will be totally 500/5 stretchs, but the fence will have one more number to be added since the fence separates the stretch into 50 pieces.</p>

<p>Let me know if you have any questions. :)</p>

4

<p>Thanks for the reply</p>

<p>For the 2nd question: How come you add only one more number? There are two posts placed at each end, so shouldn’t you add two?</p>

5

<p>See post #45 in this thread:</p>

<p><a href=“http://talk.collegeconfidential.com/sat-preparation/1493390-advanced-sat-math-strategies-those-want-800-math-3.html[/url]”>http://talk.collegeconfidential.com/sat-preparation/1493390-advanced-sat-math-strategies-those-want-800-math-3.html&lt;/a&gt;&lt;/p&gt;

6

<p>Try thinking if it this way: what if they asked you how many posts form the left-hand border of a panel? In that case, there would be 100 panels, each with one left-hand border-post. Now, over-all, does that leave out any posts? Just the one post at the right-most end of the fence. That is the only one that isn’t also a left-hand border post so it is the only one you left out.</p>

7

<p>Try google searching this site for your problems. If they come from an official TCB book, chances are that they have been answered multiple times with different solutions.</p>

<p>For your first, there is nothing easier than applying the simple formula</p>

<p>2.S1.S2 / S1 + S2 when S is the speed given in the typical SAT problem. Apply it here and you get </p>

<p>2.20.40 / 20+40 or 800/30 and 80/3. </p>

<p>Takes about 5 to 10 seconds, once you know how to recognize the problem.</p>