<p>Following is a level 5 math problem. I can't solve it myself. Help me out, guys. Show me the easiest way to solve this kind of prob. </p>
<p>19) At North High School, the ski club has 15 members and the debate club has 12 members. If a total of 11 students belong to only one of the 2 clubs, how many students belong to both clubs?
A. 2
B. 7
C. 8
D. 12
E. 16</p>
<p>Thanks in advance :)</p>
<p>8
Suppose the number of students that are in both clubs=x
no. of students only in ski club=15-x
no. of students only in debate club=12-x
total no. of students that are only in 1 club=15-x+12-x=27-2x
This is given equal to 11
So 27-2x=11
2x=16
x=8</p>
<p>what is level 5 math?</p>
<p>and congrats karan(if you couldnt do this sum then you dont deserve to go to us anyways :D)</p>
<p>Thanks, Karan11295 
Yes, it’s a level 5 prob and it’s on one of the previously administered tests.</p>
<p>Oh, I mean SAT I’s level 5 math which is usually the last two questions of each math section.</p>
<p>ok thanks for the info :)</p>
<p>19) At North High School, the ski club has 15 members and the debate club has 12 members. If a total of 11 students belong to only one of the 2 clubs, how many students belong to both clubs?
A. 2
B. 7
C. 8
D. 12
E. 16</p>
<p>Start with choice (C). Does 11+8 =15+12-8? That is 19=19? Yep, so choice (C) is the answer.</p>
<p>Notice that I computed the total number of members in 2 ways. On the left I added those that belong to only one and those that belong to both. On the right I computed ski club + debate club - both.</p>
<p>Also notice that doing this algebraically is quite difficult, but once you make a guess it’s easy to check if your guess is correct.</p>
<p>Similar questions can be easily answered by visualizing a Venn diagram.
There are two circles representing ski club and debate club with an overlapped region.
Let the overlapping area be x.
The area excluding the overlapping area=11
Total no. of students involved (total area)=11+x
While the total area also equals 15+12-x
Finally it gives the result 15+12-x=11+x</p>
<p>No algebra required here! In general, on the SAT if you are beginning a problem with “let x =…” you may want to pause and think. In this case:</p>
<p>There are 15 + 12 = 27 memberships that must be accounted for. 11 of them are held by people in only one club. 27 - 11 = 16 memberships that must be held by people in two clubs! 16/2 = 8 such people…</p>