Ratio

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Ratio

by metallicafan » Wed Nov 14, 2012 2:40 pm
What is the ratio of b to c?

(1) b is 2 more than half of c.

(2) 2b/5c = 1/2

According to the OE, in (1), we cannot convert that equation in a ratio, because the left side of the equation has two terms. Could someone please explain this? How can we be sure that this equation cannot be converted in a ratio?

OA: B

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by GMATGuruNY » Wed Nov 14, 2012 5:46 pm
metallicafan wrote:What is the ratio of b to c?

(1) b is 2 more than half of c.

(2) 2b/5c = 1/2

According to the OE, in (1), we cannot convert that equation in a ratio, because the left side of the equation has two terms. Could someone please explain this? How can we be sure that this equation cannot be converted in a ratio?

OA: B
Statement 1: b is 2 more than half of c.
b = 2 + c/2.
If c=2, then b = 2 + 2/2 = 3, with the result that b/c = 3/2.
If c=4, then b = 2 + 4/2 = 4, with the result that b/c = 4/4 = 1.
Since b/c can be different values, INSUFFICIENT.

Statement 2: 2b/5c = 1/2
(2/5)(b/c) = 1/2
b/c = (5/2)(1/2) = 5/4.
SUFFICIENT.

The correct answer is B.
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