Question:
Let * be a binary operation on the set of all nonzero real numbers, defined by $a * b=\frac{a b}{5}$ Find the value of x given that2 * (x * 5) = 10.
Solution:
To find: value of $x$
Given: $a^{*} b=\frac{a b}{5}$
$\Rightarrow x^{* 5}=\frac{5 x}{5}=x$
Now $(2 * x)=\frac{2 x}{5}$
$\Rightarrow \frac{2 x}{5}=10 \Rightarrow x=25$