HKIMO 2020 Grade 6 National Final (Heat) Set 01 Question 13

For $a\ne 3$, define $a\otimes b=\frac{3 ab}{a-3}$. Find $16\otimes(13\otimes 10)$.

Source glossary (English–Vietnamese): Operation symbol: kí hiệu phép toán; Value: giá trị.