# Special Coin Placement

Three coins are randomly placed into different positions on a $$4 \times 10$$ grid. The probability that no two coins are in the same row or column can be expressed as $$\frac{a}{b}$$ where $$a$$ and $$b$$ are coprime positive integers. What is the sum of $$a + b$$?

Details and assumptions

The coins are placed into different positions which means that no 2 coins are placed in the same square.

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