According to the diagram, if there are 18 physical science majors

Question

https://gmatclub.com/forum/download/file.php?id=88610 According to the diagram, if there are 18 physical science majors altogether, what percent of the juniors are physical science majors? A. 6% B. 20% C. 25% D. 33\frac{1}{3} % E. 50% Screenshot 2026-06-03 163116.png

gchandana · Answer

Official Explanation

Bunuel · Answer

https://gmatclub.com/forum/download/file.php?id=88610

According to the diagram, if there are 18 physical science majors altogether, what percent of the juniors are physical science majors?

A. 6%
B. 20%
C. 25%
D.  33\frac{1}{3} %
E. 50%

Physical science majors total = 18.

From the diagram, 12 students are physical science majors but not juniors.

Therefore, 18 - 12 = 6 students are both juniors and physical science majors.

Total juniors = 24 + 6 = 30.

The percent of juniors who are physical science majors is:

6/30 = 20%

Answer: B.

MartyMurray · Answer

https://gmatclub.com/forum/download/file.php?id=88610

According to the diagram, if there are 18 physical science majors altogether, what percent of the juniors are physical science majors?

Find number of students who are both juniors and physical science majors:

12 physical science majors who are not juniors

18 - 12 = 6

So, there are 6 students who are both physical science majors and juniors.

Find total juniors:

Total Juniors = Students Who Are Juniors but Not Physical Science Majors + Students Who Are Both Juniors and Physical Science Majors = 24 + 6 = 30

Answer the question asked:

Percent of Juniors Who Are Physical Science Majors = 6/30 × 100 = 20

A. 6%
B. 20%
C. 25%
D.  33\frac{1}{3} %
E. 50%

Correct answer:   B

DanTheGMATMan · Answer

https://www.youtube.com/watch?v=jcMHsCUihUo

iamyogi25 · Answer

Hi.. The question makes sense. We are looking for the intersection(6) divided by total juniors(30) which gives us 20%. 
But I have a doubt..it says "what % of juniors are physical science major". why can't we say total physical majors over total junior i.e. 18/30? I know seems absurd because we are trying to look for something which overlaps with these two categories. But if we are looking for the fundamental concepts of %, anything could be % relative to anything. why only overlap value? Not sure if I am able to explain it. Seems like I am missing something. Thank you

Bunuel · Answer

The phrase  “what percent of the juniors are physical science majors?”  means:

Out of  all juniors , what fraction are also physical science majors?

So the denominator is all juniors = 30, and the numerator must be the juniors who are physical science majors = 6.

Thus:

6/30 = 20%.

You could calculate 18/30, but that would answer a different question. The 18 includes 12 physical science majors who are  not juniors , so they cannot be counted when asking what percent  of the juniors  are physical science majors.

According to the diagram, if there are 18 physical science majors

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According to the diagram, if there are 18 physical science majors

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