If m and n are positive integers, is m/n = 3/7 ?

Question

GMAT CLUBT TESTS' FRESH QUESTION:

If m and n are positive integers, is  \frac{m}{n} = \frac{3}{7}  ?

(1)  n = 7

(2)  \frac{2}{5} < \frac{m}{n} < \frac{6}{11}

M36-85

Izzyjolly · Accepted Answer

Here is my approach. 3/7=0.42 (approx.) --> Is m=0.42*n ? (1) n = 7 --> no info about m --> Not sufficient (2) \frac{2}{5} < \frac{m}{n} < \frac{6}{11} --> 0.4 < \frac{m}{n} < 0.5 (approx.) --> 0.4*n < m < 0.5*n --> Not sufficient (1)+(2) Plugging n=7 into inequation: 0.4*7 2.8 m=3 --> \frac{m}{n} = \frac{3}{7} --> Sufficient Answer C.

Bunuel · Answer

Official Solution:

If  m  and  n  are positive integers, is  \frac{m}{n} = \frac{3}{7}  ? 
 
(1)  n = 7 . Not sufficient.
 
(2)  \frac{2}{5} < \frac{m}{n} < \frac{6}{11} . . Not sufficient.
 
(1)+(2) Plug  n = 7  into (2):
 
 \frac{2}{5} < \frac{m}{7} < \frac{6}{11} .
 
Multiply by 7:  \frac{14}{5} < m < \frac{42}{11} .
 
Approximate:  2.something < m < 3.something  .
 
Since given that  m  is an integer, then  m=3 . Sufficient.

Answer: C

Chethan92 · Answer

Clearly statement 1 is insufficient.
from 2, 0.4< m/n <0.54.
Possible values are 5/11 and 4/9 and even 3/7.
Hence insufficient.
Combining both gives N=7.
from this the only possible value is 3/7.
C is the answer.

mgundrapu · Answer

I think answer is E, we may or may not get 3/7 from combining d statements, hence E,

Posted from my mobile device

Bunuel · Answer

Par of  GMAT CLUB'S New Year's Quantitative Challenge Set

Archit3110 · Answer

#1: clearly in sufficient as no info of m given
#2: range of m/n not clear so in sufficeint

from 1&2: 2/5<m/7<6/11

or say 14/5<m<42/11
2.8<m<3.8

since m has to be an integer so only value in that range would be 3 so m=3 and n = 7 sufficient IMO C

Kinshook · Answer

Asked: If m and n are positive integers, is \frac{m}{n} = \frac{3}{7} ? (1) n = 7 Since m is unknown NOT SUFFICIENT (2) \frac{2}{5} < \frac{m}{n} < \frac{6}{11} There are infinite fractions between 2/5 and 6/11 NOT SUFFICIENT (1) + (2) (1) n = 7 (2) \frac{2}{5} < \frac{m}{n} < \frac{6}{11} \frac{2}{5} < \frac{m}{7} < \frac{6}{11} m> 14/5 = 2.8; m>2 m< 42/11 ; m<4 m = 3 since m is an integer SUFFICIENT IMO C

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If m and n are positive integers, is m/n = 3/7 ?

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If m and n are positive integers, is m/n = 3/7 ?

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