Given: (x is number of items)
Demand function: d(x)=5000.6x\displaystyle {d}{\left({x}\right)}={500}-{0.6}{x}
Supply function: s(x)=0.2x\displaystyle {s}{\left({x}\right)}={0.2}{x}

Find the equilibrium quantity:  

Find the consumers surplus at the equilibrium quantity: