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).
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Puzzle 319
How can you drop an egg exactly 30 feet …
… above a concrete floor without breaking the egg?
Answer
There are four boys and six girls in the family.
If there were B boys, and G girls we know that Billy has twice as many sisters as brothers, so 2 x (b - 1) = g.
And his sister, Frankie, 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
Subtract b from both sides gives:
b = 4
Using b = 4 in [1] gives:
2(4 - 1) = g
6 = g
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