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Advent calendar 2021
15 December
All 2021 advent puzzles
~
More information
The odd numbers are written in a pyramid.
(row 1)
1
(row 2)
3
5
(row 3)
7
9
11
etc.
What is the mean of the numbers in the 19th row?
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The mean of the numbers in the \(n\)th row is \(n^2\), so the mean of the number in the 19th row is
361
.
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sums
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range
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colouring
scales
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trigonometry
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probabilty
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ellipses
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crossnumbers
elections
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symmetry
consecutive numbers
coordinates
prime factors
money
squares
tangents
addition
bases
parabolas
logic
fractions
geometric means
taxicab geometry
gerrymandering
prime numbers
regular shapes
2d shapes
surds
games
multiples
averages
unit fractions
palindromes
percentages
dodecagons
routes
complex numbers
numbers
rugby
dice
functions
the only crossnumber
medians
quadrilaterals
indices
lines
floors
matrices
sum to infinity
factorials
doubling
menace
quadratics
3d shapes
lists
consecutive integers
crosswords
christmas
coins
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products
tiling
xor
irreducible numbers
mean
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