Question

A boy has 3 library tickets and 8 books of his interest in the library. Of
these 8, he does not want to borrow Mathematics Part II, unless Mathematics Part I is
also borrowed. In how many ways can he choose the three books to be borrowed?

Answer 1

Various cases possible are:
(i) When Maths part-I is borrowed: Here, the boy may borrow maths part-II. So, he has to select 2 books out of the remaining 7 books, which can be done in ways.
(ii) When maths part-I is not borrowed: Here, the boy will not borrow maths part-II. So, he has to select 3 books from the remaining 6 books, which can be done in ways.
∴Total number of ways = +
= 21 + 20
= 41

Answer 2

@DLS

Answer 3

Thanks

Answer 4

he is right