Suppose consumers value a high$-$quality used laptop computer at a price of $$400,$ while they value a low$-$quality used laptop at $$100.$ The supply of high$-$quality laptops is $Q_H=P_{H^{-}}-100,$ while the supply of low$-$quality laptops is $Q_L=2P_{L^{-}}50.$ Potential buyers cannot tell the difference between high$-$quality and low$-$quality laptops when purchasing one.

If the price of a used laptop is $$250,$ how many high$-$quality laptops will be offered for sale? How many low$-$quality laptops?

high$-$quality laptops:

low$-$quality laptops: