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Question

Please also explain how you got the answer. This was a math competition problem in 2005. Lets see which genius can get this one.... Wahahahahaha! First correct answer wins!!

Answer 1

E) 505

After the tide drops you have a right triangle with hypotenuse L and legs L - 10 and 100 (feet).

L^2 = (L - 10)^2 + 100^2
L^2 = L^2 - 20 L + 100 + 10000
20 L = 10100
L = 505