In College X the number of students enrolled in both a chemi

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In College X the number of students enrolled in both a chemi

by BTGmoderatorAT » Mon Oct 09, 2017 10:02 pm

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?

(1) In College X there are 60 students enrolled in a chemistry course.
(2) In College X there are 85 students enrolled in a biology course.

What's the best way to determine which statement is sufficient?

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Source: Beat The GMAT — Data Sufficiency | Mon Oct 09, 2017 10:02 pm

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by [email protected] » Tue Oct 10, 2017 4:41 pm

Hi ardz24,

We're asked to determine how much LESS the number of students enrolled in BOTH a chemistry course and a biology course is relative to the number of students enrolled in NEITHER. The wording of this prompt implies that we're dealing with a standard Overlapping Sets question, so we can use the Overlapping Sets formula to solve it:

Total = (Group 1) + (Group 2) - Both + Neither

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

Fact 1 tells us one of the Groups, but nothing else.
Fact 1 is INSUFFICIENT

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

Fact 2 tells us one of the Groups, but nothing else.
Fact 2 is INSUFFICIENT

Combined, we can fill in 2 parts of the formula:

Total = (60) + (85) - Both + Neither

There's no way to determine any of the other values though.
Combined, INSUFFICIENT

Final Answer: E

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