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This series is designed to help you step up your Data Sufficiency practice while we all spend a little extra time at home during the coronavirus situation; I’m going to publish one practice Data Sufficiency question each day! You can choose to do all of them, or none of them. 

Click on the tag “Social Distancing DS Challenge” at the bottom of this post to see all of the questions in this series! 

And remember to take whatever precautions you need to stay healthy over the next few weeks! 

Question #6

What percent of a group of people are men who are left-handed?

(1) Of the men in the group, 15 percent are left-handed.

(2) Of the women in the group, 10 percent are left-handed.

Explanation

In this scenario, there are two independent variables among members of a group: gender (men/women) and handedness (left/right). Both of the statements offer information that is specific to a certain gender in the group.

To calculate the percentage of members who have a particular handedness (left) and a particular gender (male), we need information about the percentage of one subgroup of each type. However, the information provided speaks only to handedness within a specific gender, offering no information about the intersection of groups.

In other words, since we don’t know the ratio of men to women, we can’t find the weighted value of left-handed men. So even combined, the information provided is not sufficient. The correct answer is (E).