Managers

This topic has expert replies
Legendary Member
Posts: 2789
Joined: Tue Jul 26, 2011 12:19 am
Location: Chennai, India
Thanked: 206 times
Followed by:43 members
GMAT Score:640

Managers

by GmatKiss » Sun Oct 30, 2011 11:36 pm
If ninety percent of the expected number of managers attended a conference, how many managers attended the conference?

(1) No more than ninety percent of all managers were expected to attend the conference

(2) 7 managers did not attend the conference
Source: — Data Sufficiency |

Legendary Member
Posts: 966
Joined: Sat Jan 02, 2010 8:06 am
Thanked: 230 times
Followed by:21 members

by shankar.ashwin » Mon Oct 31, 2011 12:01 am
90%(Expected) - Attended Conference.
We need to know N(Expected) to find the number.

From(1)

90%(total) > Expected. (No numbers here - Insuff)

From (2)

7 managers did not attend the conference. (Obviously this alone is not sufficient)

I am not sure here, but since (1) says, no more than 90% of all, it could be any % < 90. E IMO.

P.S: Could someone clarify if we could take it as exactly 90% of all managers for no more than 90%?

User avatar
Master | Next Rank: 500 Posts
Posts: 489
Joined: Tue Jul 05, 2011 11:10 am
Thanked: 28 times
Followed by:5 members

by gmatblood » Mon Oct 31, 2011 12:25 am
IMO:E, we are not sure on the expected managers number!

User avatar
GMAT Instructor
Posts: 349
Joined: Wed Sep 28, 2011 3:38 pm
Location: Austin, TX
Thanked: 236 times
Followed by:54 members
GMAT Score:770

by GmatMathPro » Mon Oct 31, 2011 7:27 am
I agree with E, and would also add that even if we knew the number of expected managers, it's still possible that some unexpected managers showed up. It's pretty clear that 1 and 2 are insufficient by themselves. If you knew the total number of managers, T, then the number who came would just be T-7, from statement 2. For both statements, if you can't see it for sure, to prove insufficiency, show that at least two T values are possible with both statements true:

T=100
50 expected, 50 unexpected (satisfies statement 1)
45 expected managers attended, 5 didn't (satisfies given-90% of expected attended)
48 unexpected managers attended, 2 didn't (satisfies statement 2)
overall, 93 managers attended

T=80

40 expected, 40 unexpected (satisfies statement 1)
36 expected managers attended, 4 didn't ( satisfies given-90% of expected attended)
37 unexpected managers attended, 3 didn't (satisfies statement 2)
overall, 73 managers attended

shankar.ashwin wrote:
P.S: Could someone clarify if we could take it as exactly 90% of all managers for no more than 90%?
Yes, no more than 90 implies that the percentage is less than or equal to 90.
Pete Ackley
GMAT Math Pro
Free Online Tutoring Trial