DS

[gmattester]

In a school, there are people majoring in art and also in medicine. People majoring in art are 40%, people who major in medicine are 46%. What part of the school are those who major in art but not in medicine?
(1) people who major in both are 30%
(2) people who major in neither are 26%

I am not sure about answer. I calculated E

[rishi235]

IMO D.... :roll:
Not too confy with sets either....if someone can pls explain...

Thanks

[bomond]

Here is the explanation

[gmattester]

Reason I calculated E was because I thought in Data Sufficiency questions you cannot assume total number of people (e.g when we take 100 in percentage questions).
So I was getting 2 variables because I was not assuming total number of people 100.

Can we assume value 100 for total number of people in DS questions.

[kv_ajay]

question is asking for what part of people (%) and not actual no.
So its ok to assume 100.

[bomond]

Reason I calculated E was because I thought in Data Sufficiency questions you cannot assume total number of people (e.g when we take 100 in percentage questions).
So I was getting 2 variables because I was not assuming total number of people 100.

Can we assume value 100 for total number of people in DS questions.

There is not one rule for using the number 100. It's up to you. In order to be calculation easy I used 100 same as the percentage. But you can choose number as you want. For example 200, 300 and so on. And when you find the number what are you looking for convert it into percentage and the result will be same.