12831 - Bob the Builder

All about problems in Volume 128. If there is a thread about your problem, please use it. If not, create one with its number in the subject.

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morris821028
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Re: 12831 - Bob the Builder

Post by morris821028 » Tue Oct 28, 2014 12:09 pm

In the second case, why not the result is 2 ?

{8, 20}
-----
8 + 8 = 16 (time 1)
20 + 4 = 24 (time 1)
{8, 16, 20, 24}
-----
16 + 16 = 32 (time 2)
20 + 16 = 36 (time 2)
24 + 16 = 40 (time 2)
-----
{8, 16, 20, 24, 32, 36, 40}

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brianfry713
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Re: 12831 - Bob the Builder

Post by brianfry713 » Wed Oct 29, 2014 12:56 am

I haven't solved it yet but, I don't think that's what counts as one use of the machine.
From the problem statement:
Bob takes X and using the IBM just once he can do following things:
1. Build just one child from X, let's say the child is Y.
2. Build just one child from Y, let's say the child is Z.
3. Build just one child from Z, let's say the child is Q.
And so on...

So if you use it for:
8 + 8 = 16
You could then only use it on 16 and have it count as a single use of the machine.
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brianfry713
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Re: 12831 - Bob the Builder

Post by brianfry713 » Sat Nov 01, 2014 12:57 am

start 20
L 36
end 20 24 32 36
1st use: 20 -> 24, 24 -> 32
2nd use: 20 -> 36

start 8 20
L 40
end 8 16 20 24 32 36 40
1st use: 8 -> 16, 16 -> 32
2nd use: 20 -> 24, 24 -> 40
3rd use: 20 -> 36
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Re: 12831 - Bob the Builder

Post by uDebug » Tue Feb 03, 2015 12:59 pm

I hate this login page. I always fail on it. Finally, I don't know how to login.
Have the browser remember your login credentials. That works nicely.
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