F.1 數學題

1a) The total amount Mr Lee saves in a year in terms is:
$y (1 - 40% - 35%)
= $y (25%)
= $y / 4

1b) The total amount he saves in a year is :
=($y / 4) x 12
= $3y

∴ The percentage decrease in the total amount he saves in a year is :
=｛(y/2) / (3y)｝x 100%
= 16.67 %

2012-08-15 22:25:37 補充：
The percentage decrease in the total amount he saves in a year is :
=｛(y/2) / (3y)｝x 100%
=0.1667x100%
= 16.67 %

1a.
Ans = $y(1- 40%-35%) = $y(100%- 40%-35%) = $25%y = $y/4 = $0.25y

1b.
In a year, she should have saved: $y/4×12 = $3y.
She plans to spend half of amount of salary a month ($y/2) on vocation.
So she just saves 3y - y/2 = $5y/2.
The percentage decrease in the total amount he saves in a year
= (3y - 5y/2) / 3y × 100% = (y/2) / 3y × 100% = y/6 × 100% = (16+2/3)%