Monday, 7 January 2013

Weighing Puzzles

Q1 We have one weighing balance and we can measure a thing weighing upto 100Kg and     we can put weight only on one Side. Can you tell us the minimum number of weighing bars needed to measure any weight between 1kg to 100kg.

Ans :
       i.  To start with it should be 1.
       ii. 2kg is required aftr tht and no need of 3kg bar as we can do with (2+1)
       iii.Next we need 4 kg  and not 5kg as we can use(4+1).

       So after close look we have some match i.e

       1,2,4,8,....till number less than 100 which is 64
       2^0, 2^1,2^2....till 2^6
       i.e power of 2(starting from 0 to 6). 

       So Result is 7.

Q2  We have one weighing balance and we can measure a thing weighing upto 100Kg and     we can put weight on both Sides. Can you tell us the minimum number of weighing bars needed to measure any weight between 1kg to 100kg.

Ans :
       Similar to the discussion  as above...
       Here, series goes like
       1,3,9,27,81
       3^0,3^1,3^2....till the number less than the needed

       So Result 5.
      



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