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PS weights

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PS weights

by andreasonlinegr » Thu Jan 01, 2009 6:10 pm
In a certain set of weights, for each positive integer n less than 10, there is one weight that weighs 2^n grams. What is the least number of such weights with a combined weight of 108 grams?

answer: four
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Re: PS weights

by logitech » Thu Jan 01, 2009 7:02 pm
andreasonlinegr wrote:In a certain set of weights, for each positive integer n less than 10, there is one weight that weighs 2^n grams. What is the least number of such weights with a combined weight of 108 grams?

answer: four
The powers of 2 which are less than 108 are:


2, 4, 8, 16, 32 , 64,

So you have to choose the biggest number to reach up to 108 in least number

64

Now you have to come up with 44

if you choose 32 as the second number

you are left with 44-32 = 12

So you can choose 8 and 4

So

4 + 8 + 32 + 64 = 108

4 numbers
LGTCH
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