What is the correct number of trains? At Delhi Junction an old lady put her head out of the window and asked: "Guard! How long will be the journey from
here to Hathras?" Gurard replied: "All the trains take five hours either way" Old Lady: "And how many trains shall I meet on the way?" This absurd question tickled the guard, but he was ready with his reply: "A train leaves Delhi for Hathras, and also one from Hathras to Delhi at five minutes past every hour. Right away!" The old lady calculated and found the number of trains. What is the correct number of trains?