xy ≠ 0, n = x/y, and d = 3/ (4y) + 4/ (3y)

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If xy ≠ 0, n = x/y, and d = 3/ (4y) + 4/ (3y), then what is the value of n/d?
(1) x = 2.
(2) y = 2x.
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by Anurag@Gurome » Fri Mar 02, 2012 5:11 am
sanju09 wrote:If xy ≠ 0, n = x/y, and d = 3/ (4y) + 4/ (3y), then what is the value of n/d?
(1) x = 2.
(2) y = 2x.
(1) x = 2
n = 2/y and d = 3/(4y) + 4/(3y) = 25y/12y² = 25/12y implies n/d = (2/y) ÷ (25/12y) = 24/25; SUFFICIENT.

(2) y = 2x
n = x/2x = 1/2 and d = 3/(4y) + 4/(3y) = 25y/12y² = 25/12y implies n/d = (1/2) ÷ (25/12y), which will be in terms of y; NOT sufficient.

The correct answer is A.
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by krusta80 » Fri Mar 02, 2012 5:38 am
sanju09 wrote:If xy ≠ 0, n = x/y, and d = 3/ (4y) + 4/ (3y), then what is the value of n/d?
(1) x = 2.
(2) y = 2x.
n/d = (x/y)/[3/(4y)+4/(3y)] = (x/y)/[(9+16)/12y] = 12x/25

Once this simplification is complete, the question becomes trivial...

(1) x = 2 SUFFICIENT

(2) y = 2x

INSUFFICIENT, since the formula is simply dependent on x, and we are given no numeric value for x or y.

A