[tex] \frac{an}{nc} = \frac{5}{2} [/tex]
[tex] \frac{an}{ac} = \frac{5}{7} [/tex]
[tex] \frac{cn}{na} = \frac{2}{5} [/tex]
[tex] \frac{cn}{ca} = \frac{2}{7} [/tex]
