Why do we have truth lie concept in lrdi mocks even when CAT is not asking single question from the same from past 5 years

So that you're ready for the headlines of "truth lie concept ques appears in CAT after 5 years".. ;)

before 2019 there was no set in past 20 years based on crypto arithmetic, but it still came, you should be ready for the worst case scenario

Most of the sets are those who have a very less chance of coming but still gotta be ready:-)