MATHS~ 28-40 41-42 43-44 45-46－百科全書

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MATHS~ 28-40 41-42 43-44 45-46

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28-40 http://pic.fksite.com/1181464733.JPG 41-42 http://pic.fksite.com/1181464809.JPG 43-44 http://pic.fksite.com/1181464842.JPG 45-46 http://pic.fksite.com/1181464879.JPG

最佳解答:

39) 4000(0.04) + 3000(0.12) + 2500(0.25) + 1500(0.35) + 700(0.24) = 1838 > 1800 so, buy 40) mean = [ (x1)(f1) + (x2)(f2) + ... + (xn)(fn) ] / (f1 + f2 + ... + fn) 有公式,只係加減乘除,唔好懶成咁,自己做下,唔好諗住人家幫你做埋照抄學唔到野架 41) 即係問 y-axis 係 25 時, x-axis 幾多,自己可以係圖度讀到個數,好基本 42) fourth class with class interval 41cm - 50 cm 又係基本 concept 43) 同 40 題一樣 mean = [ (x1)(f1) + (x2)(f2) + ... + (xn)(fn) ] / (f1 + f2 + ... + fn) 31.5 = [ (10)(1) + (20)(5) + (30)(8) + (40)(x) + (50)(4) ] / (1 + 5 + 8 + x + 4) 31.5 = (550 + 40x) / (18 + x) 31.5 (18 + x) = (550 + 40x) x = 2 median = 30 44) (6)(3/17) + (8)(8/17) + (6)(6/17) = 6.94 (6)(3/17) + (8)(8/17) + (8)(6/17) - 6.94 = 0.71 45a) mean = [ (x1)(f1) + (x2)(f2) + ... + (xn)(fn) ] / (f1 + f2 + ... + fn) = 5.52 b) median = 6 c) mode = 6 d) 14 + 9 + 4 = 27 46a) (w + x + y + z) / 4 = 8 w + x + y + z = 32 ------- (1) (x + y + z) / 3 = 9 x + y + z = 27 -------- (2) (1) - (2), w = 5 b) a = 71 b = 70 38 題唔同你諗, 你好懶,無鬼用