If $$\quad 5 * 5 = 10$$ ,
$$\quad 6*6=18$$
$$\quad 7*7=36$$
then $$\quad 7* 8 = ?$$
a) $54 \quad$ b) $51 \quad$ c) $30$
NOTE: Here '$*$' is not simple multiplication
It is some logic or combinations of operations from which we are getting $10$ from $5$ and $5$
Similarly, we are getting the rest of the relations via the same logic or combinations of operations
My Thoughts:
$$10= 5*(5-3)$$
i.e, LOGIC: $\quad x* (x-3) = $ RHS
Similarly $2nd$ relation is satisfied, i.e,
$$18=6*(6-3)$$
$$\text{But, } 36 \neq 7 * (7-3)$$
So, how to solve this puzzle? Any Suggestions please...
Suggestion: Let $ab=10x+y$. Then $a*b=f(x,y)$.