jmc

We have two cases:

$\bullet$ Case 1: The tens digit is three times the unit digit. In this case we have $31,$ $62,$ and $93.$

$\bullet$ Case 2: The unit digit is three times the tens digit. In this case we have $13,$ $26,$ and $39.$

Sum up the two cases: we have $31+62+93+13+26+39=\boxed{264}.$