What percentage of a day is one hour and 45 minutes?
Three pipes A, B, and C can fill the tank in 10 hours, 20 hours and 40 hours respectively. In the beginning, all of them are opened simultaneously. After 2 hours, tap C is closed and A and B are kept running. After the 4th hour, tap B is also closed. The remaining work is done by tap A alone. What is the percentage of the work done by tap A alone?