Derive the average storage requirement $($bytes per vertex$)$ of the indexed triangles representation

assuming that a vertex contains a position, a $2$D texture coord and a normal $($all $4$byte float variables$)$

and that the number of triangles is twice the number of vertices on average$\mathrm{.}13.$ Derive the average storage requirement $($bytes per vertex$)$ of the indexed triangles representation

assuming that a vertex contains a position, a $2$D texture coord and a normal $($all $4$byte float variables$)$

and that the number of triangles is twice the number of vertices on average.