7*2+6=20
7*3+3=24
7*4+1=29
so it would seem that
x$y=7x+y
if this is the case then we get
5$4=7*5+4=35+4=39
of course the issue with these kind of problems is that there are an infinite number of functions F(x,y) with which to define x$y such that the initial conditions are met. Furthermore, for any given value Z we can find an F(x,y) such that the initial conditions are met and 5$4=Z so in that sense any answer is technically a valid answer.

Posted by Daniel
on 20170504 08:37:45 