how i solve the reletionship problems

A good approach would be to first get to know the meanings of all relationships and the words used for such relationships. Then draw a generation chart, which represents the generations to which the people in the question belong to. Using this generation chart, it is quite easy to understand the relationship between the people mentioned in the question.

You can refer to the below link, which has a concept on Blood Relations:
https://cracku.in/banking/ibps-crash/blood-relations