2021 JMPSC Accuracy Problems/Problem 7

Revision as of 22:17, 10 July 2021 by Bradygho (talk | contribs) (Solution)

Problem

If $A$, $B$, and $C$ each represent a single digit and they satisfy the equation \[\begin{array}{cccc}& A & B & C \\ \times & &  &3 \\ \hline  & 7 & 9 & C\end{array},\] find $3A+2B+C$.

Solution

Notice that $C$ can only be $0$ and $5$. However, 790 is not divisible by $3$, so the number $ABC = 265$. Thus, $3A + 2B + C = \boxed{23}$

~Bradygho