Form1數!!!!!!!
There are 18 Ture-or-false questions in a Mathematics test.2 marks will be given for each correct answer and 1 mark will be deducted for each wrong answer.If Mimi answers all the questions and gets 24 marks,how many correct answer has she got?
Form1數學
2007-12-04 2:46 am
回答 (4)
2007-12-04 2:51 am
✔ 最佳答案
Let the number of questions which is correct be xthus the number of questions which is incorrect be (18-x)
2x - (18-x)(1) = 24
3x = 42
x = 14
Therefore, she has got 14 correct answer.
參考: me
2007-12-04 2:59 am
There's 18 questions
So, the full marks is 36
And she got 24
36 - 24 = 12
there's 12 questions are wrong, because she lost 12 marks
12 + 12 = 24 therefore, 6 questions are correct
2007-12-03 19:04:16 補充：
12 12 = 24 therefore, 6 questions are correct because correct questions are 2 marks each
So, the full marks is 36
And she got 24
36 - 24 = 12
there's 12 questions are wrong, because she lost 12 marks
12 + 12 = 24 therefore, 6 questions are correct
2007-12-03 19:04:16 補充：
12 12 = 24 therefore, 6 questions are correct because correct questions are 2 marks each
2007-12-04 2:58 am
X=14...
2007-12-04 2:54 am
1) X+Y=18
2) 2X+(-1)Y=24
from 1) Y=18-X
then 2)
2X-Y=24
2X-(18-X)=24
2X-18+X=24
3X=42
X=14
then Y=4
2) 2X+(-1)Y=24
from 1) Y=18-X
then 2)
2X-Y=24
2X-(18-X)=24
2X-18+X=24
3X=42
X=14
then Y=4
收錄日期: 2021-04-13 19:21:17
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071203000051KK02636