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## GMAT - Data Sufficiency - Sets

### In College X the number of students enrolled in both a chemistry course and a biology course is how much less than the number of students enrolled in neither?

In College X the number of students enrolled in both a chemistry course and a biology course is how much less than the number of students enrolled in neither?

Statement 1

In College X there are 60 students enrolled in a chemistry course.

Statement 2

In College X there are 85 students enrolled in a biology course.

Total Number of students (T) = Number of students in Chemistry(C) + Number of Students in Biology(B) - Number of students in both Biology and Chemistry(CB) + Number of students in neither(N)

we need to know

N - (C + B - CB)

Statement 1

In College X there are 60 students enrolled in a chemistry course.

We only know one parameter in the equation, hence insufficient

Statement 2

In College X there are 85 students enrolled in a biology course.

We only know one parameter in the equation, hence insufficient

Combining

We need to know total number of students and number of students in both Chemistry and Biology for which information is insufficient.

Total Number of students (T) = Number of students in Chemistry(C) + Number of Students in Biology(B) - Number of students in both Biology and Chemistry(CB) + Number of students in neither(N)

we need to know

N - (C + B - CB)

Statement 1

In College X there are 60 students enrolled in a chemistry course.

We only know one parameter in the equation, hence insufficient

Statement 2

In College X there are 85 students enrolled in a biology course.

We only know one parameter in the equation, hence insufficient

Combining

We need to know total number of students and number of students in both Chemistry and Biology for which information is insufficient.