Question
On the set of positive rationals, a binary operation * is defined by $a * b = \frac{2ab}{5}$. If $2 * x = 3^{-1}$, then x =
On the set of positive rationals, a binary operation * is defined by $a * b = \frac{2ab}{5}$. If $2 * x = 3^{-1}$, then x =