F.1 數學題 !!! 唔明.......急需

(1)
I think you mean
2/3 of a number is greater than 20% of 60 by 7. Find the number.
Let the number be x.
(2/3)x=(20)(60%)+7
2x/3=12+7
2x/3=19
x=57/2
Therefore the number is 57/2.

(2)
Jacky plans to buy a pair of shoes. Two weeks ago,he saved 40% of the selling price of the shoes. Last week, he saved 80% of the rest. This week, the shoes are on sale at a 10% discount, but he still owes $12.Find the original selling price of the shoes.

Let the original price of the shoes be $x
40%x+80%(1-60%)x+12=(1-10%)x
2x/5+8x/25+12=9x/10
20x+16x+600=45x
9x=600
x=200/3
Therefore the original price of the shoes is $200/3 or $66 and 2/3

1) Let a be the number
2/3 a= 60 x 20% +7
2/3a = 12+7
2/3a = 19
a = 19/2 x 3
a = 28.50

2) Let a be the original selling price of the shoes

a x (1-10%) - $12 = 40% x a + (1-40%) x a x 80%
0.9a - 12 = 0.4a + 0.48a
0.9a - 0.88a = $12
0.02a = $12
a = $12/0.02
a = $600