[P6] Problem Sum No. 5: Sum of Digits

A certain two-digit number is 3 times the sum of its digits. What is this number? Asked by Mark Heng Date: 26 May 2013 Source: www.algebra.com; adapted, P6 This type of problem sum certainly looks tricky — doesn’t seem like there are many clues. And it is tempting to think of one general method to solve it: Algebra! Parents, was algebra the first thing that came to your mind? Do you think there could be simpler ways to tackle...