1.if andy is 15% taller than ben and ben is 10% shorter than thomas , then andy is ____________% taller than thomas.
2. if the base if a parallelogram is increased by 25% while its area does not change, the percentage change in its height is __________?
3.when the price of petrol increased by 12% , Mr. cheung reduced his consumption by 8%. find the percentage change of his expenditure on petrol.
數學百分數題><help!!!!!
2012-01-13 2:25 am
回答 (2)
2012-01-13 3:47 am
✔ 最佳答案
1.let x be the height of thomasheight of andy
=x(1-10%)(1+15%)
=x(9/10)(23/20)
=207/200x
=(1+7/200)x
=(1+3.5%)x
andy is 3.5% taller than thomas
2.let a be the area,b be the original base
original heoght=a/b
new height=a/(b(1+25%))
=a/(5/4b)
=4a/5b
%change in its height
=(4a/5b-a/b)/(a/b)*100%
=((-a/5b)/(a/b))*100%
=(-1/5)*100%
=-20%
3.let $x be his origin expenditure on petrol
new expenditure
=x(1+12%)(1-8%)
=x(28/25)(23/25)
=644/625x
%change of his expenditure on petrol
=(644/625x-x)/x*100%
=19/625*100%
=3.04%
參考: me
2012-01-13 3:45 am
1. Let andy be 1.15 meter tall , then ben is 1m and thomas is 10/9 m.
therefore andy is 3.5 percent taller than thomas.
2. Let 1 and 2 be the height and base respectively .
1.25*x = 2
x = 1.6
Therefore the percentage increase is 60 percent .
3. Expenditure = P*Q
The new percentage = (P*1.12)*(Q*0.92)
= 1.0304*P*Q
Therefore the percentage change is + 3.04 percent .
therefore andy is 3.5 percent taller than thomas.
2. Let 1 and 2 be the height and base respectively .
1.25*x = 2
x = 1.6
Therefore the percentage increase is 60 percent .
3. Expenditure = P*Q
The new percentage = (P*1.12)*(Q*0.92)
= 1.0304*P*Q
Therefore the percentage change is + 3.04 percent .
參考: me
收錄日期: 2021-04-13 18:28:08
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120112000051KK00661