1. A hawker bought a certain number of oranges of which 2%are bad. He sold 90% of the remaining and had 49 left. How many oranges did he buy?
2. The radius of a circle is increased by 20%, find the percentage increase in area of the circle.
3. The base of a triangle is increased by 10% and its height is decreased by 10%.What is the percentage change in area of the triangle?
percentage問題3題..請求解答
2007-03-18 10:21 pm
回答 (2)
2007-03-18 10:51 pm
✔ 最佳答案
1.Let the total number of orange be a,0.98a*(1-0.9)=49
a=500
2.Let the old length of radius be a, new length of radius =1.2a
old area=a*a*3.1416
new area=1.2*1.2*3.1416
% increase=(1.44-1)/1*100%
=44%
3.Let the base and height be a,
old area=0.5*a*a=0.5*a*a
new area=0.5*1.1a*0.9a=0.495*a*a
% change=(0.495-0.5)/0.5*100%
=decrease1%
參考: Myself
2007-03-18 11:09 pm
1. 500
0.98x*(1-0.9)=49
2. 44%
cannot type the formular
3. decreased 0.1%
cannot type the formular also
0.98x*(1-0.9)=49
2. 44%
cannot type the formular
3. decreased 0.1%
cannot type the formular also
參考: by calculation
收錄日期: 2021-04-13 14:43:23
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