有幾題數學(有關%)唔多識-.-請指教

1.
(40%/75) x 100%
= (8/15)%

2.
(100L/120L) x 100%
= 83(1/3)%

3.
70 x 40%
= 28

4.
$300 x 160%
= $480

5.
x(30%) = 60
x = 60/30%
x = 200

6.
y(80%) = 120
y = 150

7.
80(a%) = 16
0.8a = 16
a = 16/0.8
a = 20

8.
7m(b%) = 49m
0.07b = 49
b = 49/0.07
b = 700

9.
客廳面積
= 80 x 30% m2
= 24 m2

10.
得分佔總分的百分數
= (48/80) x 100%
= 60%

11.
小芳每月收入
= $1500/(1 – 80%)
= $1500/20%
= $7500
=

1.
(40%/75) x 100%
= (8/15)%

2.
(100L/120L) x 100%
= 83(1/3)%

3.
70 x 40%
= 28

4.
300 x 160%
= 480

5.
x(30%) = 60
x = 60/30%
x = 200

6.
y(80%) = 120
y = 150

7.
80(a%) = 16
0.8a = 16
a = 20

8.
7m(b%) = 49m
0.07b = 49
b = 700

9.
80 x 30% m2
= 24 m2
面積是24 m2

10.
(48/80) x 100%
= 60%
小明的得分是總分的60%

11.
1500/(1 - 80%)
= 1500/20%
= 7500
他一個月的收入是7500元

一)
1. 75×40%=75×40÷100=30/100　　2. 100÷120×100%=83.3L

二)
3. 70×40%=70×0.4=28%　　　4. 300×160%=300×0.16=$48

三)求下列的味知數
5. 30%x=60
x=60÷30%
x=200
6. 80%y=120
y=120÷80%
y=150kg
7. 80×a%=16
a%=0.2
a=0.2×100
a=20
8. 7×b%=49
b%=49÷7
b%=7
b=700
9. 80m2×30%=24m2
10.48/80×100%=0.6×100%=60%
11. 設 $x為他一個月的收入
(1-80%)x=1500
20%x=1500
x=1500÷20%
x=7500
他一個月的收入是$7500

一,1)百分之三十. 2)百分之83.

二,3)28. 4)480元

三,5)X=200. 6)Y=150KG. 7)A=20. 8)B=7%.

9)客廳的面積是24m2 . 10)百分之60. 11)7500元.

第一題問題打錯了?