A problem by S rohith

Substitute a=6, b=4 and c=3. Then given expression becomes 13/12, i.e. 1.083

Write $a$ and $c$ in term of $b$ : $a=\frac{3}{2}b$ and $c=\frac{3}{4}b$ . Now bashing, $a+b+c=\frac{3}{2}b+b+\frac{3}{4}b=\frac{13}{4}b$ and $3a+3b-6c=\frac{9}{2}b+3b-\frac{9}{2}b=3b$ .

Hence , dividing we get $\frac{13}{4}b\times\frac{1}{3b}=\frac{13}{12}\approx1{,}08333$