cindy leaves school at the same time every day. if she cycles at 20\:km/h,20km/h, she arrives home at 4:304:30 in the afternoon. if she cycles at 10\:km/h,10km/h, she arrives home at 5:155:15 in the afternoon. at what speed, in km/h,km/h, must she cycle to arrive home at 5:005:00 in the afternoon?