In a group of 9 IT professionals, some work on VB, some work

Question

In a group of 9 IT professionals, some work on VB, some work on AS400, and some work on both. Each of the 9 IT professionals is involved in at least one of the projects - VB/AS400. How many IT professionals in the group work on both VB and AS400?

(1) Twice as many IT professionals in the group work on VB as work on AS400.
(2) 5 of IT professionals work on AS400.

Please explain the answer.

neeraj kaushal · Answer

I too have trouble with this question. Anyone can explain pls.

Bluebird · Answer

I think the answer is C.

Equation: VB+AS-both=9

  VB=2AS --> plug this into the equation

2AS+AS-both=9
3AS-both=9
Insufficient - we have two unknowns

  AS=5 --> plug this into the equation

VB+5-both=9
VB-both=4
Insufficient- again, we have two unknowns

  Put them together and you get:

3AS-both=9
3(5)-both=9
15-both=9
-both=-6
both=6
Sufficient - answer is C.

grad_mba · Answer

is it safe to assume that each of the 9 IT folks are involved in atleast one of the projects unless otherwise specifically stated ?

sidbidus · Answer

ya shouldn't one consider the ppl who are on bench and don't work. :-D

Juaz · Answer

Should be C.
from 1 and 2:
suppose AS400 ppl = X
then VB ppl = 2X
Both - B

9 = 5+10-B => B = 6

buffetfollower · Answer

C) it is as explained by 'Bluebird'

vshaunak@gmail.com · Answer

Yes, assume that each of the 9 IT professionals is involved in atleast one of the projects. I have edited the post.

Sergey_is_cool · Answer

I think it's C you need both equations to solve it

vshaunak@gmail.com · Answer

Think more. This is a GMAT 700+ level question

vijay2001 · Answer

Answer is A

Utlising information in (1) i.e there are 2X people knowing VB/AS400 and assuming that atleast 1 person knows both, only way this is possible is 8 people working VB/AS400 and 4 people working other and 3 people doing both.

Question needs to be more specific

The reason C cannot be true is solving both equations, we get 2X=10 people, but there are only 9 in the team.

hkfcheung · Answer

The answer has to be E

In a group of 9 IT professionals, some work on VB, some work on AS400, and some work on both. Each of the 9 IT professionals is involved in at least one of the projects - VB/AS400. How many IT professionals in the group work on both VB and AS400? 
 
9 = (V - n) + (A - n) + n
9 = V + A - n , V = VB, A=AS, n= both in VB & AS
to answer this set theory question, you need V, A & n 

(1) Twice as many IT professionals in the group work on VB as work on AS400. 
 V = 2A
Since there's 9 in the group, the possibilities are:
V A n
4 2 3
2 1 6
Insufficient 

(2) 5 of IT professionals work on AS400.
 Don't know V or n
Insufficient 

 Can you consider both?
Using data from 2, the value A = 5 cannot be used to determine one of the possible choices since there's only 9 people.
2*5 = 10

Hence, answer needs to be E

Mishari · Answer

G1: VB , G2: AS400

Total = Group1 + Group2 - Both
T = G1 + G2 - B = 9

Need to find B

 (1) Twice as many IT professionals in the group work on VB as work on AS400.  
G1 = 2G2

3G2 - B = 9

possibilities are: G2 = 4, B = 3 .. that's it.. we can't say G2 > 4 because in this case G1 = 10

 Statement 1 alone is sufficient 

 (2) 5 of IT professionals work on AS400.  
G2 = 5
G1 + 5 - B = 9 --> G1 - B = 4
4 work on G1 alone
5 work on G2 or both 

 Insufficient 

 My Answer:   A

vshaunak@gmail.com · Answer

Possible values satisfying statement1 are- V A n 8 4 3 ----> This is acceptable as n <= A and n <= V 10 5 6 ----> This is not acceptable as n>A and V > 9 (not possible) If you draw the Venn Diagram you will come to know that the professionals working in both V and A can not be greater than any of V and A. Any other values of A > 4 will not be acceptable because of the above reason. So the only acceptable values are V A n 8 4 3 Hence SUFF.

KillerSquirrel · Answer

I think you have a mistake:

possible values are:

  VB:AS400  

2:1 (sum is too small - can't be less then 9)

4:2 (sum is too small - can't be less then 9)

 6:3 (can be true ! 0 people working on both)

8:4 (can be true ! 3 people working on both) 

10:5 (can't be - (10+5)=15 , 15-9=6 meaning 6 people working on both since there are only 5 people at AS400 its false).

12:6 (same logic as 5:10)

(A) is insufficient!

vshaunak@gmail.com · Answer

OA is 'A'.
This question is made by me. This is not from any official source. Hope you have enjoyed the question.

OE:
Possible values satisfying statement1 are-
x = work on AS400
2x = work on VB
y = common between above two
x+2x -y = 9
3x-y = 9
y should be multiple of 3 to have x integer
possible values of y are 3,6,9...etc.

putting these values in equation,
y=3, x =4, 2x=8
This is acceptable as y <= x and y <= 2x

y=6, x =5, 2x=10
This is not acceptable as y>x and 2x > 9 (not possible)
If you draw the Venn Diagram you will come to know that the professionals working in both VB and AS400 can not be greater than PROFESSIONALS working individually is any of VB and AS400.

Any other values of y > 3 will not be acceptable because of the above reason.

So the only acceptable values are
y=3, x =4, 2x=8
Hence SUFF.

Statement2:
There can be many numbers satisfying the condition. So INSUFF.

Hence Answer is 'A'.

Caas · Answer

Killer Squirrel

0 can not work for both. Some should work in any way

KillerSquirrel · Answer

caas you are correct. but still i think that statement 1 & statement 2 are contradicting so the answer must be (E). vshaunak@gmail.com please acknowledge !

In a group of 9 IT professionals, some work on VB, some work

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