In 1989, Dutch ice skater Dries van Wijhe skated 200 km at an average speed of 35.27 km/h. How long was he skating? Use the formula d = rt, where d is the distance in km, r is the rate in km/h, and t is the time in hours. How long would it take to earn $6,000 in interest on a principal of $9,000 at an annual simple interest rate of 4.1%? Use the simple interest formula I = prt, where I is the interest earned, p is the principal, r is the interest rate per year, and t is the time in years.