David0822

151.东东裂变。Triple in every 30min, what is the number of it after 4 hours divided by that in 2 hours?
[确认]81
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设起始时为 X
4 hour later : (3^8)X
2 hour later : (3^4)X
[(3^8)X] / [(3^4)X] = 3^4 = 81
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David0822

∆OAB
OB = 半径 = 10
OA = 车宽/2 = 6
AB = (OB^2 – OA^2)^(1/2) = (100 – 36)^(1/2) = 8