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Dating Penny. The pennies described in the previous Mindscape attract the attention of a local coin collector who is curious about the years in which the pennies were minted. He discovers that 40% were minted in 1990 or later, 25% were minted in the 1980s, 25% in the 1970s, and 500 were minted before 1970. How many pennies were minted in 1990 or later?
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