You are walking down a straight path in a park and notice there is another person walking some distance ahead of you. The distance between the two of you remains the same, so you deduce that you are walking at the same speed of 1.25 m/s. Suddenly, you notice a wallet on the ground. You pick it up and realize it belongs to the person in front of you. To catch up, you start running at a speed of 2.75 m/s. It takes you 18.5 s to catch up and deliver the lost wallet. What distance ahead of you was this person when you started running?

(The equation of motion of an objext moving in a straight line is x = x₀ + v₀t + 1/2 at² )