This pertains to question 2 - i of September 2017 question paper of IAI. For the accident year 2012, can anyone please clarify why the split between two treaties ( 1/1/11-31/12/11, 1/1/12- 31/3/13 on risk attaching basis) is 50% each. I am thinking the diagonal needs to touch at the point 31/3/13 instead of 31/12/2012, hence the proportion is not straight 50% each. However, this has another issue making 2013 accident year to take exposure from 3 treaties. Any help is greatly appreciated Also, is there any reference on how these type of problems could be tackled. Whether these types of problems are tested in ifoa question paper. Thanks