列式比我得喇..但要計到答案
1) Find the amount of salaries tax for the following net taxable incomes: $10 000
2) If the basic allowance for a single person is $108000, find the amount of salaries tax for each of the following monthly incomes: $10 000
3) A number is first decreased by 20% and then increased by a%.The overall %change in the number is +4%.
(a) Let x be the original number.Express the final number in terms of a.
(b) Find the value of a.
help..f.3 maths~Salaries Tax
2006-10-15 9:38 pm
回答 (2)
2006-10-15 10:02 pm
✔ 最佳答案
1) 你冇% 式 =($10 000 X tax rate%)2) ($10 000 x 12) - $108 000
3) x decrease 20% = X*(1-20%)
then increase a% = X*(1-20%) * (1+a%)
計個 % change
({[X*(1-20%)]* (1+a%) - X } / X ) * 100% =4 %
b) ({[X*(1-20%)]* (1+a%) - X } / X ) * 100% =4 %
divid x so 0.8*(1+a%)- 1 = 4%
0.8*( 1+a%) = 4%+1
1+a%= 1.04/0.8
a% = 1.3 - 1
a%= 0.3
so a = 30
4 a)A= BC
A(1+8%)(1-5%)= B(1+8%)C(1-5%)
1.026A= 1.026BC
A increase by 2.6%
b) 1.08A = 1.2B * (1+a%)C (let a be the % change)
1.2 * (1+a%) = 1.08
1+a%= 1.08/1.2
a%= 0.9- 1
a%= -0.1
C have to decrease by 10%
2006-10-15 14:02:57 補充：
唔知你明唔明-.-
2006-10-15 10:15 pm
(1)
Net Taxable income = $10,000
Tax rate on the 1st $30,000 = 2% ----------------如果你條題目俾左tax rate你, 計返佢個rate
Amount of Salaries Tax = $10,000 x 2% = $200
(2)
annual income = $10,000 x 12 = $120,000
Net taxable income = $120,000 = $108,000 = $12,000
Tax rate on the 1st $30,000 = 2% ----------------如果你條題目俾左tax rate你, 計返佢個rate
Amount of Salaries Tax = $12,000 x 2% = $240
(3)(a)
x (1-20%) (1+a%) = x(1+4%)
(3)(b)
x (1-20%) (1+a%) = x(1+4%)
0.8(1+a%) = 1.04
1+a% = 1.04 / 0.8
1+ a% = 1.3
a %= 0.3
a = 30
(4)(a)
new A = B(1+8%) x C(1-5%) = 1.08B x 0.95C = 1.026BC
Therefore, A is increased by 2.6%
(b)
(1+8%)A = B(1+20%) x new C
1.08A = 1.2B x new C
new C = 1.08A / 1.2B = 0.9 A/B
Therefore, %change in C should be -10%.
Remarks: because A = BC, so C = A/B
Net Taxable income = $10,000
Tax rate on the 1st $30,000 = 2% ----------------如果你條題目俾左tax rate你, 計返佢個rate
Amount of Salaries Tax = $10,000 x 2% = $200
(2)
annual income = $10,000 x 12 = $120,000
Net taxable income = $120,000 = $108,000 = $12,000
Tax rate on the 1st $30,000 = 2% ----------------如果你條題目俾左tax rate你, 計返佢個rate
Amount of Salaries Tax = $12,000 x 2% = $240
(3)(a)
x (1-20%) (1+a%) = x(1+4%)
(3)(b)
x (1-20%) (1+a%) = x(1+4%)
0.8(1+a%) = 1.04
1+a% = 1.04 / 0.8
1+ a% = 1.3
a %= 0.3
a = 30
(4)(a)
new A = B(1+8%) x C(1-5%) = 1.08B x 0.95C = 1.026BC
Therefore, A is increased by 2.6%
(b)
(1+8%)A = B(1+20%) x new C
1.08A = 1.2B x new C
new C = 1.08A / 1.2B = 0.9 A/B
Therefore, %change in C should be -10%.
Remarks: because A = BC, so C = A/B
參考: myself
收錄日期: 2021-04-12 19:27:55
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