MathDB
P(n) and S(n)

Source:

December 3, 2005
MATHCOUNTS

Problem Statement

Let P(n) P(n) and S(n) S(n) denote the product and the sum, respectively, of the digits of the integer n n. For example, P(23) \equal{} 6 and S(23) \equal{} 5. Suppose N N is a two-digit number such that N \equal{} P(N) \plus{} S(N). What is the units digit of N N? <spanclass=latexbold>(A)</span> 2<spanclass=latexbold>(B)</span> 3<spanclass=latexbold>(C)</span> 6<spanclass=latexbold>(D)</span> 8<spanclass=latexbold>(E)</span> 9 <span class='latex-bold'>(A)</span> \ 2 \qquad <span class='latex-bold'>(B)</span> \ 3 \qquad <span class='latex-bold'>(C)</span> \ 6 \qquad <span class='latex-bold'>(D)</span> \ 8 \qquad <span class='latex-bold'>(E)</span> \ 9