• Kaustubh

MemberNov 5, 2011

## Grand Quiz Question #5

CEans,

We think this is quite tough puzzle; but certainly not for our awesome CEans. The question below carries 15 CE Coins. The puzzle is a sequence of numbers and you've to find the value of X ðŸ˜€

1, 1, 2, 1, 3, 2, 4, 1, 5, 3, 6, 2, 7, 4, 8, 1, 9, 5, 10, 3,11, 6, 12, 2, 13, 7, 14, 4, 15, 8, 16, 1, 17, 9, 18, 5, 19,10, 20, 3, 21, 11, 22, X, ...
Of course, guessing is easy - but we want you to give us a detailed explanation & logical reasoning for your answer.

As always - the fastest CEan wins.
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Replies
• MemberNov 5, 2011

6

Alternating numbers are going in series: 1 2 3....
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• MemberNov 5, 2011

Ans is 6
there are many series embedded in each other
in first there is a gap of one term between two consecutive terms
in second there is gap of three terms between two consecutive terms
in third there is gap of seven terms between two consecutive terms
in third series last term is 5 and after a gap of seven term x=6
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• MemberNov 5, 2011

so removing those series numbers we get a sequence in which we have another series in alternative sequence(index number 2, 6, 10 and so on). Following the series, we get the number.
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• MemberNov 5, 2011

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
1 1 2 1 3 2 4 1 5 3 6 2 7 4 8 1 9 5 10 3 11;

so on... the alternate numbers form increasing series.. so answer is 6.
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• MemberNov 5, 2011

x = 6

Logic:
The sequence in itself has multiple sequences alternating in between.

1, seq2, 2, seq3, 3, seq2, 4, seq3, 5,..
seq2 is again 1,2,3,4,5..
And seq3 is half the value of the 1st even number happening to it's right side

So at the end we have ..22, seq3, 23, seq2
Here the seq2 number is 12
So x=12/2 = 6
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• MemberNov 5, 2011

removing the first set of alternate terms which ar 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 we get
1, 1, 2, 1, 3, 2, 4, 1, 5, 3, 6, 2, 7, 4, 8, 1, 9, 5, 10, 3, 11, X, ...
1, 1, 2, 1, 3, 2, 4, 1, 5, 3, X, ...
1, 1, 2, 1, 3, X, ... so 6 miust come here
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• MemberNov 5, 2011

Check this out. Of course, this does not mean that I am the winner. ET, RVignesh, Varsha and CP had answered it correctly before me today.
Congos ET, CP, RVignesh and Varsha. 😀

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• MemberNov 5, 2011

1, 1, 2, 1,
3, 2, 4, 1,
5, 3, 6, 2,
7, 4, 8, 1,
9, 5, 10, 3,
11, 6, 12, 2,
13, 7, 14, 4,
15, 8, 16, 1,
17, 9, 18, 5,
19, 10, 2, 3,
21, 11, 22, x

1[SUP]st[/SUP] Sequence: 2n-1 (1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21)
2[SUP]nd[/SUP] Sequence: n (1, 2, 3,â€¦., 21)
3[SUP]rd[/SUP] Sequence: 2n (2, 4, 6,â€¦â€¦, 22)
4[SUP]th[/SUP] Sequence: 1, 1, 2, 1, 3, 2, 4, 1, 5, 3, x
Here again:
1, 1, 2, 1,
3, 2, 4, 1,
5, 3, 6, 2â€¦.and the same sequence continues.
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• MemberNov 5, 2011

in the given series we can see 2 sequences.. one is 1,2,3,4.....,22
other is 1,1,2,1,3,2,4,1.......,11 (alternating numbers of the given sequence)
the 2nd sequence above has again 2 sequences..
one is 1,2,3,4....., 11
other is 1,1,2,1,3,2,4,1,5,3,..
it contains 2 sequences again..(1,2,3,4,5 and 1,1,2,1,3)
and the missing number is the next number in the sequence 1,2,3,4,5..
that is, 6
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• MemberNov 5, 2011

the alternate series is going on...
in every series between every consecutive term there is no 1
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• MemberNov 5, 2011

its 6...after 4 dgts whn 1 coms it added wd 1(frst tym),next tym 1 is added wd 1(1+1=2),,next 2 is added wd 2(2+2=4),,at last 3 is added wd 3(3+3=6)............thas all the game!
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• MemberNov 5, 2011

X=6
consider the series as
a,b,c,d,e,f,g,...
4th number is a,
8th number is b,
12th number is c,
16th number is d...
So,
40th number is k
(i.e., k=6).
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• MemberNov 5, 2011