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UKMT Junior Kangaroo, 2016

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

In the addition sum below, $a$ , $b$ and $c$ stand for different digits.
$\begin{array}{r} a\,b\,c \\ +\,a\,c\,b \\ \hline c\,4\,a \end{array}$
What is the value of $a + b + c$ ?

(A) $20$ (B) $19$ (C) $18$ (D) $17$ (E) $16$

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