Question -
Answer -
(i) Given: there are5 books of mathematics and 6 books of physics.
In order to buy onemathematics book, number of ways is 5C1 similarlyto buy one physics book number of ways is 6C1
Hence, the number ofways a student buy a Mathematics book and a Physics book is 5C1 × 6C1 =5 × 6 = 30
(ii) Given: there isa total of 11 books.
So in order to buyeither a Mathematics book or a Physics book it means that only one book out ofeleven is bought.
Hence, the number ofways in which a student can either buy either a Mathematics book or a Physicsbook is 11C1 = 11