Female Students at College C (DS)

[Milanproda1]

Disclaimer: I searched using the following criteria: College C, 2/5 of the students, College C business majors, and College C females...came up with other questions, so my apologies if this questions does exist, I just happened to not find it.

Question:If 2/5 of the students at College C are business majors, what is the number of female students at College C?

(1)- 2/5 of the male students at College C are business majors.

(2)- 200 of the female students at College C are business majors.










OA is C.

Flustered by this question, do not know where to start.

Thanks in advance.

[blink005]

Let no. of male students be m & that of female students be f.

Given:
2/5*(m+f)= Biz. major

To find.
f

1.
2/5*m are BM
Insufficient

2.
200 f are BM
Insufficient

We have to choose between C & E

1+2

2/5*m+200=2/5*(m+f)
2/5*f=200

Hence C.

[messi10]

Hi Milanproda,

blink005 has shown you a very quick and easy way.

I will just add that this type of question can be solved by making a double set matrix. This has been explained in word translations guide, chapter 7.

Regards

Sunil

[Milanproda1]

If we skip A & B and go to C/E split:

If there are 1,000 total students:
2/5 of all students is 400. So we have 400 business majors, and 600 non-business majors.
If we have 200 female business majors, then we also have 200 male business majors, which leads us 500 total Males and 500 total females.

This situations fulfills all of the criteria as far as I can tell ( I would make a double set matrix

Business Not Business Total

Male 200 300 500

Female 200 300 500

Total 400 600 1,000

Criteria: 2/5 of all students (1,000)= 400
2/5 of male students (200 out of 500)
200 Female B-majors

Now:


Business Not Business Total

Male 40 60 100

Female 200 300 500

Total 240 360 600



Next (I am beginning to feel like an idiot....):


Business Not Business Total

Male 80 120 200

Female 200 300 500

Total 280 420 700


(Confirmation: I am special ED, I just proved my own problem).

I went through this post and realize halfway through that the number of females will always be the same. I just made so many double matrix's that I HAD to post this message, lol.

Thanks again.

[RonPurewal]

(Confirmation: I am special ED, I just proved my own problem).

lol.

[javieremartinezmunoz]

I think this is a very tricky question, what happens if

A)1/5 (and not 2/5) of the male students at College C are business majors?


I think this can not be solved .
Can anybody help me on this?

The 2/5 in total number and male number is a tricky coincidence!

Thanks

PS: in this case I think you can not say 1/2(M+F)= 1/2M+1/2F

[RonPurewal]

I think this is a very tricky question, what happens if

A)1/5 (and not 2/5) of the male students at College C are business majors?


I think this can not be solved .
Can anybody help me on this?

well... when it comes to establishing that something is NOT sufficient, testing cases is often the easiest way to go. just plug in some numbers and see if you can come up with two different results.

the individual statements don't work, for basically the same reason they don't work in the original problem. so let's skip to the point of using them together.

* let's say there are 50 male students, of whom 10 (one-fifth) are business majors.
since there are 200 female business majors, that's 210 business majors overall.
this 210 must account for two-fifths of the student population, per the prompt, so the student population is 525.
therefore there are 525 - 50 = 475 female students.

* now let's say there are 100 male students, of whom 20 (one-fifth) are business majors.
since there are 200 female business majors, that's 220 business majors overall.
this 220 must account for two-fifths of the student population, per the prompt, so the student population is 550.
therefore there are 550 - 100 = 450 female students.

that's two different results, so the answer to your new version is (e) for sure.

by the way, what you are doing here ("tweaking" the problem) is an excellent way to prepare for data sufficiency. not only does it give you extra practice, but it should also give you a healthy appreciation for just how sensitive the problems are to their initial conditions.

[javieremartinezmunoz]

Thanks Ron

[RonPurewal]

Thanks Ron

sure.