Numbers Issues in LSAT LR

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34iplaw

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Numbers Issues in LSAT LR

Postby 34iplaw » Mon Jun 27, 2016 5:52 pm

I posted this to the September group, but I figured other eyes may know the answer and/or benefit from said answer.

Does anyone know of any resources that go over the relatively few math [I use that term with hesitation, as it barely qualifies as math] issues that present themselves on the test? It seems to be typically pretty basic stuff, but I rather not be as hesitant on these.

Examples being [and I hate even using the term math as it's so basic but I just don't deal with sort of "abstract" "math" all that often right now.]

A > B + C therefore A must be greater than C. [Some question about private airport fees. Other examples could be if something isn't less than or equal it must be greater than.]

Area D is made up of A, B, and C. A, B, & C get a share of D's total revenue based on their proportion of the population. A's share decreased despite an increase in population. [Question about Ditrama, Korva, Mitro, and Guadar.]

I want to refresh to make sure I remember these things cold. Most of them are things I'm sure I know, but I don't want to waste time thinking about it on the test. Ultimately, fear of uncertainty made me pick wrong answer choices in these two cases.

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notsolawful

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Re: Numbers Issues in LSAT LR

Postby notsolawful » Mon Jun 27, 2016 8:12 pm

I remember a question, i think a must be true: 3 acres of land and an 2ox is cheaper than 1 acre of land and 1 bird. From this you were to deduce that birds are more expensive from oxen. A necessary assumption is that land has a positive price but LSAT grants you this right.

Also, know that all question are non-transitive sometimes. Most people prefer A to B, Most people prefer B to C, therefore most people prefer A to C. This is incorrect. A truly transitive property is I prefer A to B, I prefer B to C, therefore I prefer A to C. The former argument is incorrect because with most, you can move people around and it makes this false. A real world example is that most prefer Bernie to Trump, and most prefer Trump to Clinton ( I don't know if this is true but let's run with it), therefore most prefer Bernie to Clinton.

Probably the most important one is: Most of Most is some. Most skittles are red. Most red skittles are tasty. Thus, Some red skittles are tasty.

Many, some, few, when combined have no logical significance. Some cars are fast. Some fast vehicles float. No inference can be made About cars.
When you see "All" in logical statements it usually has the effect of multiplying by 1. All + Most= Most, All+ Some=some, All + no= no. No is like multiplying by 0. No + Most = no, no + some = no

Also important on the lsat is understanding per capita or average is different from particular instances. I don't know if i consider this math or not but it has the word average in it. Found usually in flaw questions i think or discrepancy. The average life expectancy has increased so Jon, who is an average man will live longer. This isn't valid.

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34iplaw

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Re: Numbers Issues in LSAT LR

Postby 34iplaw » Mon Jun 27, 2016 11:21 pm

Woops - double post.
Last edited by 34iplaw on Mon Jun 27, 2016 11:25 pm, edited 1 time in total.

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34iplaw

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Re: Numbers Issues in LSAT LR

Postby 34iplaw » Mon Jun 27, 2016 11:22 pm

Thanks - the bird and ox example is kind of what I was referring to. I know that it's not really math, but I wasn't sure the best way to label it. It's these sort of quasi-math issues that when they show up kind of throw me off my game.

You have a typo with the red skittles, but I got where you were going! You don't need the 'red' in the second premise for it to be true. I actually just did a lot of questions dealing with the quantifiers [all, some, most]... basically the skittles example is the only time you can draw a conclusion with two quantifiers.

Some conclusions you can draw from some, as it is reversible. So is most, but you have to drop it to a some... If most cars are fast vehicles then some fast vehicles must be cars. It can be useful with inference chains.

The per capita thing would be one of the sort of math things I was alluding to, but I think on the easier end of the 'maths.' The ox example is really a good example of one though. Supposedly, Trainer and other guides have these issues... I just hadn't gotten that far yet!

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notsolawful

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Re: Numbers Issues in LSAT LR

Postby notsolawful » Tue Jun 28, 2016 2:19 am

Yeah. I made a mistake with skittles. I'm a little tired. Most A are B. Most B are C. Some A are C. I'm sure you knew what I meant. The trainer does have some good stuff on that.

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34iplaw

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Re: Numbers Issues in LSAT LR

Postby 34iplaw » Tue Jun 28, 2016 9:58 am

I did and no worries!

I really appreciate the info. I'll check through the trainer now!



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