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Take a normal piece of paper, exactly 0.1 mm thick.
Fold it in half, and then in half again, and again, and again.
Do this a total of 50 times.
How thick would the final paper be (if this could be done)?
[Ref: ZOPB]
Hint: We'll assume that we can actually fold it this many times.
Answer:
Very thick indeed! The paper doubles in thickness with each fold. If we could fold it 50 times, it would be around 70 million miles thick!
1 fold would be 0.1 + 0.1 = 0.1 x 2 ^ 1 = 0.2 mm
2 folds would be 0.1 + 0.1 + 0.1 + 0.1 = 0.1 x 2 ^ 2 = 0.4 mm
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10 folds would be 0.1 x 2 ^ 10 = 102.4 mm
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50 folds would be 0.1 x 2 ^ 50 = 112,589,990,684,262.4 mm = 112,589,990.7 km (around 70 million miles).
Puzzle 974
Using the letters EEEENNNNPPSS complete this grid. The grid reads the same across as down.
Answer: There are four boys and six girls in the family.
If there were B boys, and G girls we know that Daniel has twice as many sisters as brothers, so 2 x (b  1) = g.
And his sister, Jessica, has one more sister than she has brothers, so g  1 = b + 1.
2(b  1) = g [1]
g  1 = b + 1 [2]
Using [1] in [2] gives:
2(b  1)  1 = b + 1
Expanding the bracket gives:
2b  2  1 = b + 1
Simplifying the left hand side gives:
2b  3 = b + 1
Add 3 to each side gives:
2b = b + 4
Subract b from both sides gives:
b = 4
Using b = 4 in [1] gives:
2(4  1) = g
6 = g
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