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rajatbareilly
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Let M be the maximum value and N be the minimum value of the

by rajatbareilly Sat Mar 06, 2010 6:57 am

Let M be the maximum value and N be the minimum value of the expression (x^2 + y)/y.
If a <= x <= b and c <= y <= d,
then what is the value of M - N?
(1) c = 3
(2) a = -2, b = 5 and d = 7

Will share OA later.
rajkapoor
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Re: Let M be the maximum value and N be the minimum value of the

by rajkapoor Sun Mar 07, 2010 2:30 am

express (x^2 +y)/y = x^2/y + 1

a<= x <= b
c <= y <= d

max of the expression is reached when x is max and y is minimum
hence M = b^2/c + 1

min of the expression when x is min and y is max
hence N = a^2/d + 1

M- N = b^2/c - a^2 /d

Statement 1) c = 3 - doesn't help evaluate M - N expression
Statement 2 ) doesn't help evalue m - N expression

Statement 1) and 2) together help evaluate M - N ,
therefore C)
i ask so i can answer / i answer so i can learn
Ben Ku
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Re: Let M be the maximum value and N be the minimum value of the

by Ben Ku Tue Mar 16, 2010 2:57 am

Please cite the source (author) of this problem. We cannot reply unless a source is cited (and, if no source is cited, we will have to delete the post!). Thanks.
Ben Ku
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ManhattanGMAT