Question

Garen observed his athletic friends, Aya and Marisa, run. The two girls ran in a 1.5-km straight dirt road. Marisa was a given a ten-second head-start. When Aya ran, she caught up with Marisa, who ran at 3.75 m/s. Both of them finished the 1000 m run, with Aya measured to finish the track at 375 seconds. How fast was Aya?

Answer 1

Time for Aya, who ran at constant velocity, is the road distance divided by her time:

$$v=d/t=1500/375=4\text{ m/s}.$$