Hi,

It’s a pretty-straight forward sets question.

You can use venn-diagrams to solve the sets questions.

Question: How many students chose exactly one of the subject (i.e., history or geography) ?

Statement I is insufficient:

The number of students in the room who are taking at least one of the subjects history and geography is 127.

Given, no. of students who took atleast one of the subjects is equal to 127.

But we want students who chosen exactly one subject.

From the below diagram,

We can see that, if we know the number of students who chosed both, we can find the answer.

Statement II is insufficient:

The number of students in the room who are taking both geography and history is 46.

Now we can clearly see that, statement II individually not sufficient.

But combining both I and II, we will get the answer.

That is, 127 – 46 = 81.

So the answer is C.

Hope this helps.

Regards,

Junaid.

Byjus GMAT Quant Expert

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