Are all of the terms in Set A equal?
(1) The sum of all 14 terms in Set A is 98.
(2) The sum of any 3 terms in Set A is 21.
OA C
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Are all of the terms in Set A equal?
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I posted a solution to a very similar problem here:
https://www.beatthegmat.com/from-og-12-t73239.html
https://www.beatthegmat.com/from-og-12-t73239.html
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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Target question: Are all of the terms in Set A equal?BTGmoderatorDC wrote:Are all of the terms in Set A equal?
(1) The sum of all 14 terms in Set A is 98.
(2) The sum of any 3 terms in Set A is 21.
Statement 1: The sum of all 14 terms in Set A is 98
There are several possible scenarios that satisfy this statement. Here are two.
Case a: Set A = {7,7,7,7,7,7,7,7,7,7,7,7,7,7} in which case all of the numbers ARE equal
Case b: Set A = {0,0,0,0,0,0,0,0,0,0,0,0,0,98}, in which case all of the numbers are NOT equal
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: The sum of any 3 terms in Set A is 21
Under most conditions this statement WOULD be sufficient.
However, if set A has only 3 terms in total, then the statement is NOT sufficient.
To see what I mean, consider these two possible scenarios that satisfy statement 2:
Case a: Set A = {7,7,7} in which case all of the numbers ARE equal
Case b: Set A = {0, 0, 21}, in which case all of the numbers are NOT equal
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
The combined statements ARE sufficient. Here's why:
Let's let a,b,c and d be four of the 14 numbers in set A.
From statement 2, we know that a + b + c = 21
Notice that if I replace ANY of these three values (a,b or c) with d, the sum must still be 21 (according to statement 2)
This tells us that a, b and c must all equal d.
I can use a similar approach to show that all of the other numbers must also equal d.
This means that all of the numbers in set A must be equal.
Since we can answer the target question with certainty, the COMBINED statements are SUFFICIENT
Answer: C
Cheers,
Brent