(1) m is between 40 and 80.
(2) m is between 50 and 90.
OA is E. I need an explanation.
Thank you..
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Data sufficiency
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Brent@GMATPrepNow
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Target question: Is m between 35 and 75 ?Newaz111 wrote:Is m between 35 and 75 ?
(1) m is between 40 and 80.
(2) m is between 50 and 90.
Statement 1: m is between 40 and 80
This statement doesn't FEEL sufficient, so I'm going to TEST some values.
There are several values of m that satisfy statement 1. Here are two:
Case a: m = 55, in which case m IS between 35 and 75
Case b: m = 76, in which case m is NOT between 35 and 75
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT
Aside: For more on this idea of plugging in values when a statement doesn't feel sufficient, you can read my article: https://www.gmatprepnow.com/articles/dat ... lug-values
Statement 2: m is between 50 and 90.
This statement doesn't FEEL sufficient either, so let's TEST some values.
There are several values of m that satisfy statement 2. Here are two:
Case a: m = 55, in which case m IS between 35 and 75
Case b: m = 76, in which case m is NOT between 35 and 75
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
There are still several values of m that satisfy BOTH statements Here are two:
Case a: m = 55, in which case m IS between 35 and 75
Case b: m = 76, in which case m is NOT between 35 and 75
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT
Answer = E
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Brent
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Matt@VeritasPrep
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S1 gives 40 < m < 80. m could be 79, which is out of range, or 64, which is in range. NOT SUFFICIENT
S2 gives 50 < m < 90. m could be 51, which is in range, or 79, which is out of range. NOT SUFFICIENT
Together, the lower boundary is 50 and the upper boundary is 80. So 50 < m < 80 and again m could be 51 or 79.
S2 gives 50 < m < 90. m could be 51, which is in range, or 79, which is out of range. NOT SUFFICIENT
Together, the lower boundary is 50 and the upper boundary is 80. So 50 < m < 80 and again m could be 51 or 79.
