Puzzle 1
What letter completes this square in the most logical manner?
Y
G
W
A
K
L
?
O
Z
J
P
D
V
F
T
H
Note: this puzzle is not interactive, and the squares cannot be clicked.
Puzzle Copyright © Kevin Stone
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Hint
Look at the letter positions in the alphabet.
Answer
R.
If you take the alphabetic positions of each letter in a row, the total is always 56.
Double-Checking
Y + G + W + A = 25 + 7 + 23 + 1 = 56
K + L + R + O = 11 + 12 + 18 + 15 = 56
Z + J + P + D = 26 + 10 + 16 + 4 = 56
V + F + T + H = 22 + 6 + 20 + 8 = 56
Puzzle 2
How many squares of any size on this chessboard do not contain a rook?
Puzzle Copyright © Kevin Stone
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Hint
There are no squares of size 5 x 5.
Answer
There are 125 squares without a rook.
Reasoning
61 squares of size 1 x 1
39 squares of size 2 x 2
20 squares of size 3 x 3
5 squares of size 4 x 4
Giving a total of 61 + 39 + 20 + 5 = 125 squares.
Puzzle 3
Which is larger:
square feet in half a square mile
cubic yards in a cubic furlong
Puzzle Copyright © Kevin Stone
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Hint
There are 3 feet in a yard, 1760 yards in a mile, and 8 furlongs in a mile.
Answer
Square feet in half a square mile.
Reasoning
There are 3 feet in a yard, 1760 yards in a mile, and 8 furlongs in a mile.
A mile is 1760 x 3 = 5280 feet in a mile.
A square mile is 5280 x 5280 = 27878400 square feet.
Therefore, half a square mile = 13,939,200 square feet.
A furlong is 1760 ÷ 8 = 220 yards.
Therefore, a cubic furlong is 220 x 220 x 220 = 10,648,000 cubic yards.
Puzzle 4
Can you find a number such that …
… its double is fourteen more than its quarter?
Puzzle Copyright © Kevin Stone
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Hint
The number is less than 20.
Answer
8.
Reasoning
We need a number (N) such that:
2 x N = 14 + N
———
4
Multiply throughout by 4 to give:
8 x N = 56 + N
So:
7 x N = 56
So N = 8.
Double-Checking
Its double is 16.
Its quarter is 2.
So its double is fourteen more than its quarter.
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