1. If z : ( z + 3 ) = 5 : 6, find the value of z/
2. A sum of money is divided into two portions in the ratio of 5 : 7. If the smaller portions is $1300, find the amount of the sum.
3. A post is painted in black and white in the ratio of 3 : 2. If the length of the white portions is 4 m,find the length of the post.
f.1 maths(ratio & rate)
2008-02-16 9:23 pm
回答 (2)
2008-02-16 9:39 pm
✔ 最佳答案
1. 你可以將比例化為分數 Steps 如下:z/(z+3) = 5/6 (然後交叉互乘)
6z=5(z+3)
6z=5z+15
6z-5z=15
z=15 (你可以將15代入z, 可以試下work唔work)
2. 設x為總數
1300:(x-1300) = 5:7
1300/(x-1300) = 5/7
5(x-1300)=7(1300)
5x-6500 = 9100
5x=9100+6500
5x=15600
x=15600/5
x=3120
3. 設y為總長
(x-4)/4 = 3/2
2(x-4) = 3(4)
2x-8 = 12
2x = 20
x=10
Hope they helped!
參考: my brain
2008-02-16 9:34 pm
1. z/(z+3) = 5 / 6 --> 6z=5z+15 --> z=15
2. Let Total Sum be S --> S*(5/12)=1300 --> S = $3120
3. Let X be the length of portions of black --> x / 4 = 3 / 2 --> x=6 Therefore Total Length of post is 10m
2. Let Total Sum be S --> S*(5/12)=1300 --> S = $3120
3. Let X be the length of portions of black --> x / 4 = 3 / 2 --> x=6 Therefore Total Length of post is 10m
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