The diet region in the figure has corners $(0, 12)$, $(2, 4)$ and $(10, 0)$. Food B costs $6$ rupees a kilogram, and food A costs $p$ rupees. For which $p$ do the plans $(2, 4)$ and $(10, 0)$ cost the same?

Fig. 1: A graph of an unbounded region above and to the right of a broken boundary with corners at (0, 12), (2, 4) and (10, 0). One edge runs from (0, 12) down to (2, 4) and the next from (2, 4) to (10, 0). The shading continues past the top and right edges of the picture, with arrows showing that it does not end. The three corners are marked with dots and labelled. The axes are labelled packs of food A and packs of food B.