Jeremiah LaBrash: Variables in Answer Choices with Distance Rate Time GMAT Problem

Variables in Answer Choices with Distance Rate Time GMAT Problem

If Susan takes 9 seconds to run y yards, how many minutes will it take her to run x yards at the same rate?

Jeremiah LaBrash

Susan takes 9 seconds to run

y

yards, then her rate is

R a t e = \frac{D i s t a n c e}{T i m e} = \frac{y}{9}

yards per second.

To run

x

yards at this rate she'll need

T i m e = \frac{D i s t a n c e}{R a t e} = \frac{x}{(\frac{y}{9})} = \frac{9 x}{y}

seconds, which is

\frac{9 x}{60 y}

B

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