GMAT Challenge Series (700+): Q16

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Question:

Brenda and Sally run in opposite direction on a circular track, starting at diametrically opposite points. They first meet after Brenda has run 100 meters. They next meet after Sally has run 150 meters past their first meeting point. Each girl runs at a constant speed. What is the length of the track in meters?
 

A. 250

B. 300

C. 350

D. 400

E. 500

MBA Wisdom's Answer:

$$\text{Meeting points:}$$ $$\textit{1st time: Brenda and Sally, together, run half of the circumference}$$ $$\textit{2nd time: Brenda and Sally, together, run the full circumference}$$ $$$$ $$\text{Brenda:}$$ $$\textit{1st time: Brenda runs 100m}$$ $$\textit{2nd time: Brenda runs 200m (twice as far as the 1st time)}$$ $$$$ $$\text{Sally:}$$ $$\textit{2nd time: Sally runs 150m}$$ $$$$ $$\textit{Length of the track} = {200} + {150} = {350}$$

C. 350