Gisele trains 7 days per week for a biathlon. She covers a total of 20 miles cycling and running each day. Gisele cycles a total of 105 miles each week, and runs a certain number of miles per week. If she cycles the same number of miles each day and runs the same number of miles each day, the equation StartFraction 1 over 7 EndFraction (105 + r) = 20 represents the situation. Which describes the solution, r, to this equation?