sets problem

[crazy4gmat]

Club Number of Students
Chess 40
Drama 30
Math 25

The table above shows the number of students in three clubs at McAuliffe School. Although no student is in all three clubs, 10 students are in both chess and drama, 5 students are in both chess and math, and 6 students are in both drama and math. How many different students are in the three clubs?
(A) 68
(B) 69
(C) 74
(D) 79
(E) 84

[coolaman]

C. 74

[crazy4gmat]

explanation please

[getsetgo]

..C
Use venn diagram method to solve this question,it becomes crystal clear.

Chess 40, 25 chess+10 chess and drama+5 chess and math
Drama 30 ,14 drama+10 chess and drama+6 drama and math
Math 25 ,14 math+5 chess and math+6 drama and math

[shobby]

C+D+M = C only + D only + M only + CnD only + CnM only + DnM only + CnDnM
=> 40+30+25 =
C only + D only + M only + 10 + 5 + 6 + 0
=> C only + D only + M only = 95 - 21 = 74
Ans C