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N and reverse N

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October 14, 2005
calculusintegration

Problem Statement

How many two-digit positive integers N N have the property that the sum of N N and the number obtained by reversing the order of the digits of N N is a perfect square? <spanclass=latexbold>(A)</span> 4<spanclass=latexbold>(B)</span> 5<spanclass=latexbold>(C)</span> 6<spanclass=latexbold>(D)</span> 7<spanclass=latexbold>(E)</span> 8 <span class='latex-bold'>(A)</span>\ 4\qquad <span class='latex-bold'>(B)</span>\ 5\qquad <span class='latex-bold'>(C)</span>\ 6\qquad <span class='latex-bold'>(D)</span>\ 7\qquad <span class='latex-bold'>(E)</span>\ 8