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Recent questions tagged isi2015-pcb-a

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ISI2015-PCB-A-3
Consider all possible permutations of eight distinct elements $a, b, c, d, e, f, g, h$. In how many of them, will $d$ appear before $b$? Note that $d$ and $b$ may not necessarily be consecutive.
Consider all possible permutations of eight distinct elements $a, b, c, d, e, f, g, h$. In how many of them, will $d$ appear before $b$? Note that $d$ and $b$ may not nec...
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3 votes
1 answer
2
ISI2015-PCB-A-2
Prove that in any sequence of $105$ integers, there will always be a subsequence of consecutive elements in the sequence, whose sum is divisible by $99$.
Prove that in any sequence of $105$ integers, there will always be a subsequence of consecutive elements in the sequence, whose sum is divisible by $99$.
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