Data Sufficiency : Some Good Questions

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Data Sufficiency : Some Good Questions

by premnath » Thu Jul 28, 2011 10:08 am
Dear Friends,
I have come across some good DS questions and wish to share will all of you. Here are the first few...


Directions: This data sufficiency problem consists of a question and two statements labeled (i) and (ii). You have to decide whether the data given in the statements are sufficient for answering the question.

A. Statement (i) alone is sufficient, but Statement (ii) alone is not sufficient.
B. Statement (ii) alone is sufficient, but Statement (i) alone is not sufficient.
C. Both Statements (i) and (ii) together are sufficient, but neither statement alone is sufficient.
D. Each statement alone is sufficient.
E. Statements (i) and (ii) together are not sufficient.

1. At St. Xaviers' College, the ratio of students who participate in either the dance program or the Choral program to students who participate in singing is 5 to 7. How many students participate in singing?
(i) The number of students who participates in either dance or choral program is prime.
(ii) The total number of students who participates in dance or choral & singing program are 360.

2. If P is a positive integer, is the greatest common factor of 118 & P, a prime number?
(i) P < 7
(ii) P is an even number.

3. One adult and ten children are in an elevator. Find the average weight of the adult and the children.
(i) Weight of adult is more than the weight of a child.
(ii) The adult's weight is 4 times the average weight of children.

Cheers,
Prem Nath
Source: — Data Sufficiency |

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by winniethepooh » Thu Jul 28, 2011 1:57 pm
What are the OA's?

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by ColumbiaVC » Thu Jul 28, 2011 3:42 pm
1. D
2. B
3. E

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by edge » Sat Jul 30, 2011 6:28 pm
premnath wrote:1. At St. Xaviers' College, the ratio of students who participate in either the dance program or the Choral program to students who participate in singing is 5 to 7. How many students participate in singing?
(i) The number of students who participates in either dance or choral program is prime.
(ii) The total number of students who participates in dance or choral & singing program are 360.
I have a question here... since there is no information about whether there are students who take part in all three activities, are we to assume that there are none? In that case, my answer is B, because St2 tells us that n(D or C) = 150 and n(S) = 210.

But this conflicts with the information in St1, which though insufficient by itself, should not be incompatible with St2 if I properly understand the format of DS questions. Experts?

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by Avinash_Tyagi » Sat Jul 30, 2011 10:32 pm
My answers were:

[spoiler]1)B
2)B
3)E[/spoiler]

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by madhumita0808 » Sun Jul 31, 2011 3:43 am
My answers were:
1. B
2. D
3. E

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by naveen451 » Mon Aug 01, 2011 11:41 pm
1.D
2.C
3.E

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by neerajkumar1_1 » Tue Aug 02, 2011 3:37 am
hi ...
just on a quick look.. .

the first question...
I would go for D...

but i feel the question is not a gmat question...
if the ratio is 5:9...

and the first statement says The number of students who participates in either dance or choral program is prime, then in that case... there is only one solution... i.e 5... any other multiple will give a non prime answer...

one can solve with both the statements...
but a gmat problem will give u a consistent answer...

hope it helps..