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In a 10-kilometer race, each runner runs 5 km to point P and returns to the start by the same route. Ian runs 4 kilometers per hour faster than Sean. Ian runs to point P, turns around, and meets Sean 3 km from the start. Assume that Ian and Sean each maintain a constant speed and start at the same time. What is Sean's time, in minutes, for running the 10 kilometers?

 Apr 4, 2021
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While sam runs $3$ km, Ian runs $5+2=7$ km. So Ian is running $\frac{7}{3}$ as fast as Sam. Then $(s+4)=\frac{7}{3}s$. Now compute $s$ and finish.

 Apr 4, 2021

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