Question #dded5

1 Answer
P dilip_k
Jul 24, 2016

#"No. of novel"=3#

#"No. of books of poem"=4#

#"No. of dictionary"=1#

#"Total No. of books"=3+4+1=8#

(i)
3 books can be chosen from total 8 books in #""^8C_3# ways.Keeping dictionary a fixed choice other 2 books can be chosen from rest 7 books in #""^7C_2# ways.

Hence the probability that among the three chosen book one is the dictionary,is #(""^7C_2)/(""^8C_3)=21/56=3/8#

(ii)
Amongst the 3 books chosen there wii be 1 novel and 2 books of poem.This can be done in #""^3C_1 xx""^4C_2# ways.
So the probability of this choice will be #(""^3C_1 xx""^4C_2) /(""^8C_3)=(3*6)/56=9/28#

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