Let us assume Tom age is $x$ then:
- Dick’s age= $3x$
- Harry’s age=$2.3x=6x$
Now according to the given question, Dick’s age is 1 year less than the average age of all three,
$\therefore 3x=\left (\frac{3x+6x+x}{3} \right )-1$
$\Rightarrow 3x=\left (\frac{10x}{3} \right )-1$
$\Rightarrow 1=\frac{10x}{3}-3x$
$\Rightarrow 1=\frac{10x-9x}{3}$
$\Rightarrow 1=\frac{x}{3}$
$\Rightarrow x=3$
So Tom age is $3$ year,
Harry’s age is $=6x=6*3=18$ year.
$\therefore$ Harry’s age is $18$ year.