Question
Thu January 03, 2013 By: Aditi Bhatnagar
 

The number of natural numbers which are less than 2*100000000 and which can be written by means of the digits 1 and 2.

Expert Reply
Mon January 07, 2013
Answer : To find : The number of natural numbers which are less than 2*100000000 and which can be written by means of the digits 1 and 2
 
As the number should be less then 2 00000000 therefore by using principle of counting 
on the first place { from ryt} 1 and 2 digit both can be used , going to the 8th position , but the 9th position {from ryt } can have only 1 digit as putting 2 would increase the no. from 200000000,
therefore the no. of such no required are = 1* 2*2*2*2*2*2*2*2 = 256 Answer 
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