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[昔日明報]
【明報專訊】■Game 1
1. B
2. A
3. C
■Game 2
B
■Game 3
Pat's speed: 4.5 m/h
Bill's speed: (4.5+0.4) m/h
Time needed: t
4.5×t+4.9×t = 23.5
(4.5+4.9)×t = 23.5
t = 23.5÷(4.5+4.9)
= 2.5 hours
[Smarties' Power English 第219期]