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Range of squares - SET

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Range of squares - SET

by gmatrant » Fri Aug 06, 2010 4:26 pm
Set S consists of n positive integers. What is the range of squares of n positive integers?
A. The largest number is S minus the smallest number in S is 5
B. The average of the numbers in S is 6
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by sanju09 » Fri Aug 06, 2010 10:30 pm
gmatrant wrote:Set S consists of n positive integers. What is the range of squares of n positive integers?
A. The largest number is S minus the smallest number in S is 5
B. The average of the numbers in S is 6

If a is the smallest and b is the greatest positive integer of the n positive integers in the set S, then what is b^2 - a^2?

(1) It says b - a = 5. Cannot answer b^2 - a^2 with this alone. Insufficient

(2) It says that the sum of remaining n - 2 positive integers in the set S is 6 n - (a + b). This is far away from the chief query. Insufficient

Even when taken together, we are [spoiler]not getting b + a in contrast to b - a[/spoiler] to answer the chief query.

[spoiler]E[/spoiler]
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by freakinmaniac » Fri Aug 06, 2010 11:06 pm
the second statment says : average of all numbers =6 ; so max+min/2 = 6
so max+min=12.

now we have two equations and we can solve for max and min.
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by sanju09 » Fri Aug 06, 2010 11:17 pm
freakinmaniac wrote:the second statment says : average of all numbers =6 ; so max+min/2 = 6
so max+min=12.

now we have two equations and we can solve for max and min.
That was true only if the integers were consecutive or equally spaced as in an arithmetic progression. This is no where mentioned in the question.
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
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