Tom bought 300 durians at $2.50 each. After throwing away 30 bad ones, he sold the remaining good ones and found that he earned $600, what was the selling price of each durians?
Tom bought 300 - 30 = <<300-30=270>>270 good durians.
He spent a total of 2.50 x 300 = $<<2.5*300=750>>750 for the 300 durians.
So his profit was $600 - $750 = $<<600-750=-150>>150.
Therefore, the selling price of each durians is $750 / 270 = $<<750/270=2.78>>2.78. Answer: \boxed{2.78}.