A small business sells handcrafted items. The revenue \( R \) from selling \( x \) items is given by the equation \( R = 50x \). The cost \( C \) to produce \( x \) items is given by \( C = 20x + 300 \). At what number of items sold will the revenue be equal to the cost? Let's think step by step and output the final answer within \boxed{}.
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