John rode his bicycle to town at the rate of 15 milles per hour. He left the bicycle in town for minor repairs and walked home along the same route at the rate 3 miles per hour. Excluding the time John spent in taking the bike into the repair shop, the trip took 3 hours. How many hours did John take to walk back?

Apne doubts clear karein ab Whatsapp par bhi. Try it now.