Rahul takes 40 minutes to reach his school from home. On a certain day, he left for his school at 8:00 am but when he was at \(\frac{1}{4}th \) of the distance between his school and house, he remebered to have forgotten a book. He returned back home, took the book and immediately left for school again. If during the entire journey he maintains a constant speed and time he spent in his house is neglected , then he will reach school at -