Each of the 105 students in a certain club is either a freshman, sopho

Question

Each of the 105 students in a certain club is either a freshman, sophomore or junior. How many of the students in the club are sophomores?

(1) The ratio of the number of freshmen to the number of sophomores is 1 to 2

(2) The ratio of the number of freshmen to the number of junior is 1 to 4

maratikus · Answer

1: insufficient - no info about juniors
2: insufficient - no info about sophmores

1&2: ratio of freshman:sophmores:junionrs = 1:2:4 -> sophmores = (2/7)*105 = 30 -> sufficient

misterJJ2u · Answer

C.

(1) insufficient; only know ratio of fresh to soph; 3 variables required;
(2) insufficient; only konw ratio of fresh to juniors; 3 variables required;
(together) sufficient; 1(x) + 2(x) + 4(x) = 105; 7x=105

EMPOWERgmatRichC · Answer

Hi All,

Here, we have a relatively straight-forward DS question. For many Test Takers, it's an easy prompt to "talk" through. On Test Day though, for Test Takers who end up with a score that is lower than expected, the most common reason is SILLY MISTAKES. To that end, you can PROVE the correct answer to this question with just a little bit of note-taking and REMOVE the possibility of a silly mistake happening here.

We're told that there are 105 students, comprised of Freshmen, Sophomores and Juniors. We're asked for the number of Sophomores.

For organizational purposes, I'm going to assign variables:

F = # of Freshmen
S = # of Sophomores
J = # of Juniors

F + S + J = 105

Fact 1: The ratio of F:S = 1:2

We can TEST VALUES to prove there's more than one possibility:

IF....
F = 1
S = 2
J = 102
The answer to the question is 2

F = 2
S = 4
J = 99
The answer to the question is 4
Fact 1 is INSUFFICIENT

Fact 2: The ratio of F:J = 1:4

Again, we can TEST VALUES to prove there's more than one possibility:

IF...
F = 1
J = 4
S = 100
The answer to the question is 100

F = 2
J = 8
S = 95
The answer to the question is 95
Fact 2 is INSUFFICIENT

Combined, we know...
F:S = 1:2
F:J = 1:4

We can combined these ratios into one "big" ratio:
F:S:J
1:2:4

With this ratio and the 105 total students, we CAN figure out the number of each.

F:S:J
15:30:60
The answer to the question IS 30
Combined, SUFFICIENT

Final Answer:  C

GMAT assassins aren't born, they're made,
Rich

anairamitch1804 · Answer

Consider first (1) alone. 
Ratio of the number of freshmen to the number of sophomores is 1 : 2. 
We need more information regarding number of juniors to answer the question. 
So (1) alone is not sufficient.

Next consider (2) alone. 
Ratio of the number of freshmen to the number of juniors is 1 : 4. 
This is not sufficient because we need some information about sophomores as well. 
So (2) alone is not sufficient. 
Next combine both the statements together and check. 
On combining, we have that ratio of the number of freshmen to the number of sophomores to the number of juniors 
is 1 : 2 :4. 
Or number of sophomores is 2/(1+2+4) = (2/7)*105 = 30.

The correct answer is (C).

bumpbot · Answer

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Each of the 105 students in a certain club is either a freshman, sopho

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GMAT Data Sufficiency (DS) Questions

Each of the 105 students in a certain club is either a freshman, sopho

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