A sat math question

Test Preparation SAT Preparation
1

<p>in a survey of 63 people,23 people subscribe to magazine A,21people subscribed to magazine B,and 17 people subscribed to magazine C.For any of the two magazines,4 people subscribed to both magazines but not to the third magazine. if 5 people in the survey did not subscibe to any of the three magazines,how many people subscribed to all three magazines.</p>

<p>ok, there is a formula that may useful in this question:
T=A+B+C-m-2p+N</p>

<p>where T is the total number; A,B,C represent the three magazines. m means number of people select two of the magazines; p means people subscribed to all three magazines.
N=none which means people who did not choose any of the magazines in the survey.</p>

<p>so:</p>

<p>63=23+21+17-4*3+5-2p</p>

<p>but it turns out like this:</p>

<p>9=-2p
which is not right AT ALL</p>

<p>don't know what i did wrong........hope u guys can help me</p>

2

<p>Looks to me like the question is flawed.</p>

3

<p>I agree with Dr. Steve. Also, in all of my experience with SATs, I have never seen an overlapping groups question this complicated on a real test. Usually it’s just two groups and there are members that are shared between the two groups (Total = Group A + Group B + Neither Group - Both Groups).</p>

4

<p>I have actually seen a few questions involving three overlapping groups - they can show up as one of the last two questions on a section. But I agree that there hasn’t been anything of this difficulty level (as far as I’ve seen). A question of this level could appear on the subject tests though.</p>