Special number

The given number was $\overline{ab}$ so we can write it as $\overline{ab}=10\times a+b$ $b=a-1$ $a+b=\dfrac{\overline{ab}}{6}$ so, $a+a-1=\dfrac{10\times a+b}{6}$ $2a-1=\dfrac{10a+a-1}{6}$ $12a-6=11a-1$ $a=5$ $b=a-1=5-1=4$ Hence the given number is $10a+b=54$