Political systems

$A={{W_{1}\sum R_{1}}+{W_{2}\sum R_{2}}+{W_{3}\sum R_{3}}+... \over {W_{1}\sum N_{1}}+{W_{2}\sum N_{2}}+{W_{3}\sum N_{3}}+...}$

a=b

c=d

i = 10

y = 20

b = i + y