Câu hỏi:
Twelve flags stand equidistant along the track at the stadium. The runners start at the first flag.
Đáp án:
Not 12 seconds. There are 7 segments from the first flag tot the eighth, and 11 from the first to the twelfth. He runs each segment in 8/7 seconds; therefore, 11 segments take 88/7= 12 4/7 seconds.
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