Wednesday, November 17, 2010

Mocktest 1st paer 10 Ans

10.The citizens of planet nigiet are 8 fingered and have thus developed their decimal system in base 8. A certain street in nigiet contains 1000 (in base 8) buildings numbered 1 to 1000. How many 3s are used in numbering these buildings?
192
64
54
256

Solution.Ans is 256
In base 8 digits 0-7 exist and 1000 can be represented as 1750 in base 8.
So it needs 256 no.of 3's to number from 0 to 1750 when calculated

4 comments:

  1. sorryyy friends above question answer is 192 not 256 I dont know the complete procedure.If known anybody post it

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  2. hi friends
    there is no difference between calculating 3 for 1000 and 777(1000-1).
    below 777 means any 3 digit no(we take 1 as 001)
    a 3-digit no is _ _ _.
    now fix 3 at single digit place means _ _ 3 - then 64 3's
    now fix 3 at 8-base digit place means _ 3_ - then 64 3's
    now fix 3 at 64-base digit means place 3 _ _ - then 64 3's
    now all are 192 3's

    ReplyDelete
  3. and also we give base 8 for 1000 not base 10. so no need for conversion

    ReplyDelete