[F. 3 Maths] Percentages (2 questions)
1. Kathy is 18% shorter than Jason, and Timpthy is 20% taller than Kathy. Compare the heights of Jason and Timothy, who is taller? By what percentage?
2. The numbers of boys and girls in school are in the ratio 7 : 3. If th number of boys is decreased by 10% and that of girls is increased by 40%, find the percentage change in the total number of students.
[F. 3 Maths] Percentages (2 questions - 10 points)
2007-09-24 3:56 am
回答 (1)
2007-09-24 4:08 am
✔ 最佳答案
Let Xcm be the height of KathyJason' height=
X / (1-18%)
=100x/82
Timpthy's height=
X x (1+20%)
=120x/100
Jason is taller.
Let K be the total number of the students.
7K/10 x (1-10%)
=56K/100
3K/10 x (1+40%)
=42K/100
98%K students left.
So, the % change in the total number of students is 2%.
參考: ME!
收錄日期: 2021-04-18 18:11:45
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https://hk.answers.yahoo.com/question/index?qid=20070923000051KK04648