Puzzle 2
At the local BrainBashers Sunday School meeting, the teacher brought in some puppies.
There were 20 more children than puppies.
In the corner of the room, within the ant's nest, the number of ants was 10 times the number of children.
In total, including the teacher, the children, the puppies, and the ants, there were 1440 legs in the room.
How many children attended?
Puzzle Copyright © Kevin Stone
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Hint
Work out the total number of legs.
Answer
23 children (46 legs).
With 230 ants (1380 legs), 3 puppies (12 legs), and 1 teacher (2 legs).
If we call the number of puppies P, then there were (P + 20) children and 10 x (P + 20) ants, and a single teacher. If we now count the legs, we get:
Puppies:
P x 4 = 4P
Children:
(P + 20) x 2 = 2P + 40
Ants:
10 x (P + 20) x 6 = 60P + 1200
Teacher: 2
A total of 66P + 1242
Giving:
66P + 1242 = 1440
66P = 198
P = 3
So there were 3 puppies, hence 23 children.
Puzzle 3
Can you find a five-digit number that …
… if you place a 9 at the beginning is four times larger than if you place a 9 at the end instead?
Puzzle Copyright © Kevin Stone
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Hint
Adding 900,000 to the numbner is the same as placing a 9 at the beginning.
Answer
23,076.
Reasoning
Placing the 9 at the beginning is equivalent to adding 900,000 (for example, 12,345 + 900,000 becomes 912,345).
Placing the 9 at the end is equivalent to multiplying by 10 and adding 9 (for example, 12,345 x 10 + 9 becomes 123,459).
Let's call the unknown number k, and we know that one of these numbers is 4 times the other, so:
k + 900,000 = 4 x (10k + 9)
k + 900,000 = 40k + 36
900,000 − 36 = 40k − k
899,964 = 39k
899,964 ÷ 39 = k
Therefore, k = 23,076.
Double-Checking
9 23,076 = 4 x 230,769 .
Puzzle 4
Hidden in the grid below are six hidden animals.
The letters are in sequence, but you move from letter to letter using the moves of a chess knight.
Once you have crossed off all of the animals, you will be left with seven unused letters.
What animal do these letters spell?
The moves of a knight are:
Note: this puzzle is not interactive, and the letters cannot be clicked.
Puzzle Copyright © Kevin Stone
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Hint
The L in the top row is the start of one of the animals.
Answer
Hamster.
The hidden animals are leopard, elephant, antelope, giraffe, kangaroo, goat.
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