Ratio of two number

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Ratio of two number

by mgmt_gmat » Thu Feb 11, 2010 5:25 am
20) If m, r, x & y are positive, is the ratio of m to r equal to the ratio of x to y?
a. Ratio of m to y is equal to ratio of x to r
b. Ratio of m + x to r + y equals ratio of x to y

Please explain.
Source: — Data Sufficiency |

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by thephoenix » Thu Feb 11, 2010 8:17 am
question: m/r=x/y????

s1)m/y=x/r---->m/x=y/r----->if y/r=1(its possible) or else not...insuff

s2) m+x/r+y=x/y

now from q m/x=r/y----->m+x/x=r+y/y----->m+x/r+y=x/y

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by ajith » Thu Feb 11, 2010 8:44 am
mgmt_gmat wrote:20) If m, r, x & y are positive, is the ratio of m to r equal to the ratio of x to y?
a. Ratio of m to y is equal to ratio of x to r
b. Ratio of m + x to r + y equals ratio of x to y

Please explain.
The Question is

whether m/r = x/y

a.) insufficient => m/y =x/r doesnt tell anything about x/y
b) (m+x)/(r+y) =x/y

Cross multiplying

(r+y)x =( m+x)*y

rx = my
m/r = x/y

Sufficient

B
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