The ratio of R to S is 3 to 5, what ........

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The ratio of R to S is 3 to 5, what ........

by Vincen » Tue Feb 13, 2018 3:46 am
The ratio of R to S is 3 to 5, what is the value of the ratio (R + K)/(S + K)?

(1) R = 12
(2) K = 7

The OA is the option C.

How can I get the correct answer using both statements? Experts, may you help me? Thanks in advanced.

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by DavidG@VeritasPrep » Thu Feb 15, 2018 12:46 pm
Vincen wrote:The ratio of R to S is 3 to 5, what is the value of the ratio (R + K)/(S + K)?

(1) R = 12
(2) K = 7

The OA is the option C.

How can I get the correct answer using both statements? Experts, may you help me? Thanks in advanced.
Rephrase the original question. If R/S = 3/5, then S/R = 5/3 and S = (5/3)R. Replace S with (5/3)R in the original expression to get our new question:
What is the value of (R + K)/((5/3)R + K)?

Statement 1: nothing about K. Not sufficient.
Statement 2: nothing about R; Not sufficient.

Together. We're looking for (R + K)/((5/3)R + K); Clearly, if we have values for R and K, we can just plug those values into the expression, and we have a unique value: (12 + 7)/((5/3)12 + 7) Together the statements are sufficient. The answer is C
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