勁急呀 F1數學問題(英文) 20點

唔會計答案,d式自己參透下,咁淺都唔識,上到去仲難
10)320x(1-37.5%)
11)21÷(1+5%)
12a)(5.7-6)/6x100%
12b)Last month:1000*6This month:1000*5.7∴Last month can be exchange more HKDThe difference:6000-570013a)48230÷(1+6%)13b)48230-4550014)102+102÷(1-15%)15)14.6x(1-18.25%)16a)2400*(1+10%)16b)2640÷(1-40%)17a)[48+2)-48/50]x100%17b)[48-(48-1.2)]/48x100%18a)12000x(1+12%)18b)12000x(1+12%)x(1-30%)19)numerator:2x(1+50%),denominator:5x(1-20%)20a)200x(1-10%)x150x(1-6%)20b)[200x150-200x(1-10%)x150x(1-6%)/200x150x100%21a)Letx be the score of team A at the beginning　　x(40%)=80　　x=80/40%21b)[240-80/40%]/80/40%

2012-11-22 18:53:42 補充：
21a)Let x be the score of team A at the beginning
仲有d題解自己寫,題目有晒,考試唔會有人幫到你

2012-11-22 18:55:42 補充：
上面打漏,下面先正確
20b) [200x150-200x(1-10%)x150x(1-6%)/200x150] x100%

10.the no. of students:
320 * (1-37.5%)
=320* 62.5%
=200

11. the no. of friends:
21/ (1+5%)
=21/105%
=20

12a % decrease:
(6-5.7) /6 *100%
=0.05*100%
=5%