Fractions/Ratios/Decimals

[swerve]

At a certain university, the ratio of the number of teaching assistants to the number of students in any course must always be greater than 3:80. At this university , what is the maximum number of students possible in a course that has 5 teaching assistants?

A. 130
B. 131
C. 132
D. 133
E. 134

The OA is D

Source: GMAT Prep

[Jay@ManhattanReview]

At a certain university, the ratio of the number of teaching assistants to the number of students in any course must always be greater than 3:80. At this university, what is the maximum number of students possible in a course that has 5 teaching assistants?

A. 130
B. 131
C. 132
D. 133
E. 134

The OA is D

Source: GMAT Prep

Let's do the reciprocal of the given ratio; so the ratio of students to teaching assistants must be LESS than 80 : 3.

80 : 3 => (80/3) : 1

Since the no. of teaching assistants is 5, the ratio [5*80)/3] : [1*5] => (400/3) : 5 must be less than 80 : 3.

(400/3) : 5 => 133.33 : 5

The maximum possible value close to 133.33 is 133. The value 134 would make the ratio greater than 80 : 3, not acceptable.

Correct answer: D

Hope this helps!

-Jay
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Manhattan Review GMAT Prep

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