Days of the year on which Kamla fasted: 1, 3, 6, 10, 15, 21, 28.... Days of the year on which Bimla fasted: 1,4, 8, 13, 19, 26, 34.... It can be analysed that if Kamla fasted on the Kth day, Bimla must have fasted on the (K - 2)th day. Hence for both of them to fast on the same day, Kamla must fast on some (K - 2)th day and Kth day as well. This is impossible as in the first series no two consecutive terms will have a difference of 2 after the first two days.