Question 313389
In a certain grade 9 class, there are 15 students in the choir and 12 in the drama
club.
 The number of students who are in both the choir and drama club, is the
same as the number of students who are in neither. 
How many students are in the class?
:
Let x = no. in both choir & drama
also x = no. in neither
:
Total students consist of 4 groups
15 - x = no. in Choir only
and
12 - x = no. of Drama club only
and
x = both
and
x = neither
:
Total = (15-x) + (12-x) + x + x
T = 27 - 2x + 2x
T = 27 total students