Pwn the SAT

[SilverAurora]

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@SimplyBMW

Can someone explain number 20 to me? It is the only one I do not understand.

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20. The lowest score on the most recent chemistry exam in Professor Wren’s class was a 39, and the highest score was a 75. Which inequality could be used to determine whether a particular score, s, could have come from Professor Wren’s class?</p>

<p>(A) |s – 39| ≤ 75
(B) |s – 20| ≤ 57
(C) |s – 18| ≤ 55
(D) |s – 60| ≤ 17
(E) |s – 57| ≤ 18

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<p>From the question, you can deduce that s is greater or equal to 39 and less than or equal to 75.</p>

<p>39 ≤ s ≤ 75</p>

<p>Which of the answer choices simplify to the above inequality? Well, for each absolute value inequality, there are two normal inequalities. Find the easier of the two normal inequalities by simply taking off the absolute value. By doing so, I can quickly calculate that neither (A), (B), (C), nor (D) total up to 39 or 75. (Do you get what I’m doing here? I can elaborate more if needed.)</p>

<p>That leaves (E). You can check the answer if you would like.
|s – 57| ≤ 18
s – 57 ≤ 18 so s ≤ 75
s - 57 ≥ -18 so s ≥ 39</p>

<p>39 ≤ s ≤ 75</p>