F.5 MATHS..........................
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F.5 MATHS
2010-09-24 12:23 am
回答 (1)
2010-09-24 12:29 am
✔ 最佳答案
Let x km/h be his speed in still water :12/(x+4) + 12/(x-4) = 412(x-4) + 12(x+4) = 4(x+4)(x-4)24x = 4(x^2 - 16)6x = x^2 - 16x^2 - 6x - 16 = 0(x + 2)(x - 8) = 0x = -2(rejected) or x = 8The man's rowing speed in still water is 8 km/h
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