SAT Math Question - Please help

Test Preparation SAT Preparation
1

<p>Ok heres the question:</p>

<p>Set X has x members and set Y has y members. Set Z consists of all members that are in either set set X or set Y with the exception of k common members (k > 0). Which of the following reporesents the number of members in set Z?</p>

<p>A.) x + y + k
B.) x + y - k
C.) x + y + 2k
D.) x + y - 2k
E.) 2x + 2y - 2k</p>

<p>Heres is the approach I took:</p>

<p>The members of set X: x
The Members of set Y: y
Common Members: k</p>

<p>Set Z consists of members of set X and members of set Y with exception of k, so Z must be x + y - k or choice (B) however this is wrong. What is the best way to approach this question?</p>

<p>Any help appreciated :)</p>

2

<p>X = x
Y = y
-> X+Y = [(x-k) +(y-k)] + 2k = Z + 2k
-> D</p>

3

<p>^Exactly. Remember that you have to count the ones that belong to both sets twice, since it’s asking you for the ones that belong to either of the two sets but not both. Drawing a venn diagram may help as well.</p>