Analysis: (1) Suppose this mall buys X pairs of sports shoes for the first time, then the quantity of the second purchase is 2x pairs. According to the key sentence "the price of each pair is higher than that of 20 yuan", the equivalence relation can be obtained: the unit price of the first purchase of sports shoes +20= the unit price of the second purchase of sports shoes. According to the equivalence relation, the equation can be listed, and the solution of the equation can be obtained after testing.

(2) Let the price of each pair be Y yuan. According to the quantitative relationship: (total selling price-total buying price) ÷ total buying price ≥20%, list inequalities and solve inequalities.

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