A girl scout is taking a 10.00-km hike to earn a merit badge. while on the hike, she sees a cliff some distance away. she wishes to estimate the time required to walk to the cliff. she knows that the speed of sound is approximately 343 meters per second. she yells and finds that the echo returns after approximately 2.00 seconds. if she can hike 1.00 km in 10 minutes, how long would it take her to reach the cliff?