Source: Revised GRE PDF 1st Ed. Section 6: Math; #20 (p. 89)

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# Which of the following statements must be

Which of the following statements must be true? Indicate all such statements. The number of males majoring in physical sciences is greater than the number of females majoring in that area., Students majoring in either social sciences or physical sciences constitute more than 50 percent of the total enrollment., The ratio of the number of males to the number of females in the senior class is less than 2 to 1.

### 1 Explanation

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Chris Lele, Magoosh Tutor

Sep 26, 2012 • Comment

peter paz

I dont understand why you add 30% +24%, because the sentence says the word or and not with. Can you explain me please?

, Magoosh Tutor

Hi Peter! :D

Happy to help! :) The reason we add the percents is because of the word "or." We can count people in either of those groups in answering the question. The question asks if people majoring in social science or physical science is more than 50% of enrollment.

Imagine if we had a line of people, and we walked down the line asking people what their major is. In one column we would put a mark for social science or physical science and in the other column we would put a mark for any other major. By the time we get to the end of the line, we will have more checks in the first column than in the second column. That means more than 50% of people in the line are either majoring in social science or physical science.

Does that make sense?

I hope that this helps! Happy Studying!

anik alam

if I say either Donald trump or Hilary will win the election that does not mean both Hilary and trump win. here is clearly say or so why do we need to add up? but your logic running down the line is not also denyable

Cydney Seigerman, Magoosh Tutor

Hi Anik :)

Happy to help! In your example, the options are mutually exclusive, meaning that only one of the two options can happen: either Trump wins the election or Clinton wins the election. Both cannot win. In this practice problem, we are considering students who major in either the social sciences and physical sciences together: for this question, the two groups we are comparing are student majoring in one of the two types of sciences (i.e., social and physical) or something else. Since we are considering students majoring in any of the sciences in one group, we add those percentages.