Erina89 wrote:

Hi Bunuel,

could I not just come up with a total number of stundents in order to calculate from S1 the number of female MIS stundents and from S2 the number of male stundents so that I can afterwards calculate the precent of female students in the MIS class?

Where am I going wrong? I somehow always ended up with ~29%.

Thanks for your help.

Best

Let me try to answer. The issue with %ages in DS questions is that you will get different values for different total student number.

Case 1, lets say total students are = 100 ---> S1 gives females in MIS as 0.05*100 = 5

Case 2, lets say total students are = 200 ---> S1 gives females in MIS as 0.05*200 = 10

Thus, you get 2 different answers for the same question, what is %age (wrt total students) of females in MIS. This is the reason why S1 is not sufficient. Your approach would have worked for PS questions but for DS questions be wary of the percentages when the total number is not provided.

Hope this helps.