2) In the first history test, Steven and Mandy got the same mark. In the second histiry test, Steven's score was 15% higher than the first test, while Mandy got 14 marks less than the first test. Steven got 26 marks higher than Mandy in the second test.
a) Find their scores in the first history test.
b) Find the percentage decrease in Mandy's score.
列式+過程 PLZ,,, THX =]
F1 數學(20 Marks)
2007-05-06 12:43 am
回答 (1)
2007-05-06 5:01 am
✔ 最佳答案
X = steven's marks at second histiry testY = mandy's marks at second histiry test
Z =steven''s and mandy's mark at first history test
X = Z(1+15%)
Y = Z-14
X-Y = 26
(Zx115%)-(Z-14) = 26
Zx115%-Z+14 = 26
Zx115%-Z = 26-14
Zx15% = 12
Z = 12/15%
Z = 80
B) (14-80)/80x100%= -85.2
vary easy!!
參考: my mind
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