In an examination for final student of a school 60 offered history, 50 economics and 48 literature, 30 Offered history and economics 16 Offered history and literature 22 offered economics and literature if 10 candidates offered all the three subject find 1: the number that offered history
2:the number that offered only economics
3:the number that offered only literature
4:how many candidates sat for the examination assuming that each candidate sat for at least one subject​