Solution: Represent the times as $(x, y)$ in a 60-minute square. The condition $ y \geq x + 20 $ defines a triangular region with base $ 60 - 20 = 40 $ minutes. The area of this region is $ \frac{1}{2} \times 40^2 = 800 $. The total area is $ 60^2 = 3600 $. The probability is $ \frac{800}{3600} = \frac{2}{9} $.

Sun, 19 Apr 2026 15:02:50 +0000

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