6.10 SAT Math - Logic

Logic questions don't show up on the SAT math section that often, but what they are asking you to do is make a reasonable conclusion based on a presented set of facts.  Traditional logic questions take the form known as "If P then Q."  This means that they'll tell you an "If" statement, followed by a "then" statement, and ask if that is a logical conclusion.  Example:

16. If the following statement is true: "If Martin lives in Farrowville, then Martin lives in Lascow," which of the following statements must also be true?

(A) If Martin lives in Farrowville, then Martin does not live in Lascow.
(B) If Martin lives in Lascow, then Martin lives in Farrowville.
(C) If Martin does not live in Lascow, then Martin does live in Farrowville.
(D) If Martin does not live in Lascow, then Martin does not live in Farrowville.
(E) If Martin does not live in Farrowville, then Martin does not live in Lascow.

The easiest way to solve these questions is to simply substitute in your own city and state, or information of you own choosing, like "apples are fruits" or "peanut butter and jelly makes a sandwich."  In the above example, city and state is simplest, so simply use your own.  Let's say you live in San Francisco.  Then you also live in California.  (A) says that if you live in San Francisco then you do NOT live California, obviously false.  (B) says that if you in California, then you live in San Francisco.  That doesn't have to be true, so B) is out.  (C) says that if you do not live in California then you do live in San Francisco, which makes no sense.  (D) says that if you do not live in California then you do not live in San Francisco, which definitely IS true, but just to be safe we'll check E), which says that if you do not live in San Francisco then you don't live in California, which also doesn't have to be true, so the answer is D).

Keep in mind on logic questions that "some" can mean one or more.  So if the question you were given said "All wiggums are made of alloyed metal and some wiggums are painted blue," not only should you remember to sub in your own information that makes more sense to you (for example, you could change it to "All apples are fruit and some apples are red," or even "All fans of Family Guy are funny, and some are also hot."  Use whatever works for you.), but you should also remember when you go to the answers that 'some' might mean just one.