160 How many students?

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160 How many students?

by ern5231 » Tue Oct 13, 2009 3:02 am
A class has 25 individuals - Seniors/Juniors who study/don't study chemistry. How many junior students are there?

(1) Senior students who study chemistry = 12
(2) Junior students who do not study chemistry = 10
Last edited by ern5231 on Tue Oct 13, 2009 3:41 am, edited 1 time in total.
Source: — Data Sufficiency |

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by bullzeye » Tue Oct 13, 2009 3:38 am
I think it's E.

Consider this:

Ss - Seniors that study chemestry
Sd - Seniors that don't study chemestry

Js - Juniors that study chemestry
Jd - Juniors that don't study chemestry

so we will have Ss+Sd+Js+Jd = 25

statement 1 -> Ss=12
Statement 2 -> Jd=10

They are both alone and together are insufficient to solve the equation above (we don't need to find Js and Jd separately, actually). Unless I'm missing sth.

What's the official answer?