“On another occasion, I went to his room to have lunch with him. The Fist World War had started sometime earlier. I had in my hand a copy of the monthly Strand Magazine which at that time used to publish a number of puzzles to be solved by readers. Ramanujan was stirring something in a pan over the fire for our lunch. I was sitting near the table, turning over the pages of the Magazine. I got interested in a problem involving a relation between two numbers. I have forgotten the details; but I remember the type of the problem. Two British officers had been billeted in Paris in two different houses in a long street; the door numbers of these houses were related in a special way; the problem was to find out the two numbers. It was not at all difficult. I got the solution in a few minutes by trial and error.
MAHALANOBIS: (In a joking way), Now here is a problem for you.
RAMANUJAN: What problem, tell me. (He went on stirring the pan).I read out the question from the Strand Magazine.
RAMANUJAN: Please take down the solution. (He dictated a continued fraction).The first term was the solution which I had obtained. Each successive term represented successive solutions for the same type of relation between two numbers, as the number of houses in the street would increase indefinitely. I was amazed.
MAHALANOBIS: Did you get the solution in a flash?
RAMANUJAN: Immediately I heard the problem, it was clear that the solution was obviously a continued fraction; I then thought, “Which continued fraction?” and the answer came to my mind. It was just as simple as this.