maths

1. (1+10%)(1+10%)(1+10%)=?
1.331

2. 500x2.5%x1.5=?
18.75

3. 18x(1+15%)=?
20.7

4. 36x(1-30%)=?
25.2

5. 3/12%=?
25

原值100 新值? 百分數增減 +3%
103

k x (1+10%)=77 求k
k=70

k x(1-10%)=90 求k
k=100

1. (1+10%)(1+10%)(1+10%) = 1.1 * 1.1 * 1.1 = 1.331
2. 500 * 2.5% * 1.5 = 500 * 0.025 * 1.5 = 18.75
3. 18 * (1+15%) = 18 * 1.15 = 20.7
4. 36 * (1 - 30%) = 36 * 0.7 = 25.2
5. 3 / 12% = 3 / 0.12 = 25
原值100 新值? 百分數增減 +3%
=> 新值 = 100 * (1 + 3%) = 100 * 1.03 = 103
k *(1+10%)=77 求k => k * 1.1 = 77 => k = 77/1.1 = 70
k *(1-10%)=90 求k => k * 0.9 = 90 => k = 90 / 0.9 = 100

註：這些問題要先將百分數化作小數, 即是 x% = x / 100

1. 3.3
2. 18.75
3. 20.7
4. 25.2
5. 0.36

1.1k=77
k=70

0.9k=90
k=100

2007-07-20 23:11:55 補充：
1. 1.331

1. = (1 + 10%)^3 = 1.1^3 = 1.331
2. = ...禁計算機姐－　－...教你禁...
5 0 0 x 0 . 0 2 5 x 1 . 5 = 答案
3. = 18x1.15 = 20.7
4. = 36 x 0.7 = 25.2
5. 3/12% = 3/12/100 = 300/12 = 25
新值 = 100 x (1 + 3%)因為多左３％ = 100 x 1.03 = 103
k = 77/(1+10%)
k = 77/1.1(注: 1% = 1/100)
k = 70
---------
k = 90/(1-10%)
k = 90/0.9
k = 100

好多都係禁機就ok...

1. 331

2. 18.75

3. 20.7

4. 25.2

5. 25%

100 +3% 新值=103

k=70

k=100

希望幫到你啦！！(^Ｖ^)