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a boy  has 3 library tickets and 8 books are of his interest. Of these 8,he doesn't want to borrow maths part 2, unless maths part 1 is also borrowed? In how many ways can he choose the 3 books to be borrowed ?

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

  • 32
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 ur ans should be 41

if he gets both 1 nd 2 part of the maths book= 6C1  +

if he gets his first oart of math but doesnt get the second one= 6C2  +

IF he didnt get 1 nd 2 part of maths book then=6C3

adding 6C1+6C2+6C3

we get 6+15+20= 35+6

  =41 

  • 4

If he gets both 1 nd 2 part of the maths book= 6C1 +

If he didnt get 1 nd 2 part of maths book then=6C3

adding 6C1+6C3

we get 6+20=26

i guess there should be no case fo only 1 st part or only 2nd part because he will take both of them or none of them.

  • -8
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