Puzzle 1
If one small rabbit can dig a warren in nine hours, a medium rabbit can dig a warren in 6 hours, and a large rabbit can dig a warren in four and a half hours.
How long will it take one small, one medium, and one large rabbit, to dig a warren if they all work together?
Puzzle Copyright © Kevin Stone
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Hint
How much of a warren can each rabbit dig in one hour?
Answer
2 hours.
Reasoning
The small rabbit can dig a warren in nine hours, so digs 1 /9 in one hour.
The medium rabbit can dig a warren in 6 hours, so digs 1 /6 in one hour.
The large rabbit can dig a warren in four and a half hours, so digs 1 /4.5 in one hour.
1 Hour = 1 /9 + 1 /6 + 1 /4.5
To make the denominators all the same, we can multiply through by 18 /18 to give:
1 Hour = 2 /18 + 3 /18 + 4 /18
1 Hour = 9 /18
1 Hour = 1 /2
So in one hour, they have dug half a warren, the whole warren will therefore take 2 hours.
Puzzle 2
Can you draw a continuous line that goes through every number in order, starting with 1, and ending with 6?
You can only move horizontally and vertically, every square must be visited, and the line must not cross itself.
Note: this puzzle is not interactive, and the numbers cannot be clicked.
Puzzle Copyright © Cihan Altay
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Hint
From the 1 go straight down.
Answer
Puzzle 3
Which word is the odd one out:
seventy
brawl
clover
proper
carrot
swing
emerged
crafty
travel
sacred
stone
plunge
Puzzle Copyright © Kevin Stone
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Hint
Try removing some letters.
Answer
Carrot.
Reasoning
Each of the other words remains a real word if you remove the first and last letter:
s-event -y
b-raw -l
c-love -r
p-rope -r
c-arro -t *
s-win -g
e-merge -d
c-raft -y
t-rave -l
s-acre -d
s-ton -e
p-lung -e
Puzzle 4
Which is larger, the number of seconds in a day or …
… the number of hours in 10 years?
Puzzle Copyright © Kevin Stone
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Hint
Do leap years make a difference?
Answer
Hours in 10 years.
Reasoning
In a day, there are 60 x 60 x 24 seconds = 86,400 seconds.
In 10 years, there are 10 x 365 x 24 hours = 87,600 hours, which even without the leap years is already the larger number.
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