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Alternating terms
Evening. I recently stayed in a Novotel in Barcelona, and on the doors of the lifts were a number of puzzles to keep you (slightly) amused whilst waiting.
And for the life of me, I couldn't solve this one. The next number in the sequence, reading vertically down, should be one of the five at the bottom.
I'm hoping it's just a mental blind spot I've got for this one puzzle, rather than a sign of some greater failing of faculties! Any thoughts?
25
Alternating terms
After that it would be 33, 30, 54, 35, 87, 40
One sequence goes up by 5 each time: 10, 15, 20, 25, 30, etc.
One sequence is the sum of the previous two terms: 9, 12, 21, 33, 54, etc.
And they alternate: 10, 9, 15, 12, 20, 21, 25, 33, 30, 54, etc.
Last edited by Mr Curta; 31st July 2019 at 19:12.
Pretty easy really tbh. I must have twigged it within 5 seconds.........
..........of reading Matthew's posts
Of course.
By such logic it's also the first digit of n interleaved sequences where n > 6 so the last number can, by definition, be anything.
I like the Gaudi lizard motif.
Very Wittgensteinian. :)Originally Posted by catch21
Best wishes,
Bob
There is a slow worm on the right
If a hen and a half can lay an egg and a half in a day and a half,...
If you like these puzzles, you'd love this channel:
https://youtu.be/vaitsBUyiNQ
He's going over 8÷2(2+2) that's currently viral (if you can't see the YouTube video above).
So it's alternating two different series? Dammit - feels like a cheat to me!
Thanks for the replies, and I'll check out that YouTube channel!
My thoughts exactly! I guess you're supposed to spend long enough to spot that there is no sequence that (easily) fits all the numbers so there must be more than one sequence interleaved. Better hope you're on the 52nd floor.
There are just enough terms given to allow for it to be two alternating sequences and still give you a chance of working out what they are. Of course the suggestion that there could be any number of interleaved sequences and consequently any answer is valid, but it certainly wouldn't be very fair.
Not the best puzzle TBH and it would have been a lot harder without the choice of answers given.
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