4) Jessica and Martin start riding their bicycles towards each other at 2 pm. At 2 pm, they are 25 miles apart. Jessica rides he
r bike at a constant rate of 15 miles per hour and Martin rides his at a constant rate of 10miles per hour. At 2 pm, a bird starts flying towards Martin. As soon as the bird gets to Martin, it turns back around and flies towards Jessica, and continues going back and forth until Jessica and Martin meet. The bird travels at a constant rate of 45 miles per hour. How far does the bird fly from the time it starts until Jessica and Martin meet? Assume that it takes the bird no time to turn around and fly the other direction.
