Question -
Answer -
(i)┬аGiven: there are5 books of mathematics and 6 books of physics.
In order to buy onemathematics book, number of ways is┬а5C1┬аsimilarlyto buy one physics book number of ways is┬а6C1
Hence, the number ofways a student buy a Mathematics book and a Physics book is┬а5C1┬а├Ч┬а6C1┬а=5 ├Ч 6 = 30
(ii)┬аGiven: 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┬а11C1┬а= 11