Conjoints work the same way only backwards. If you've got a feasibility relation \$$\Phi \colon X \nrightarrow Y \$$ and you want it to be the conjoint of some function \$$G \colon Y \to X\$$, you need

\$$\Phi(x,y) = \text{true} \$$ iff \$$x \le G(y) \$$.

But in Puzzle 207, which is about buying loaves of bread, the obvious first guess would be a function \$$G\$$ such that

\$$y\$$ dollars can buy \$$G(y) \$$ loaves of bread.