X+X * 0.28 x9 = 3588.2%

x+0.0252x=3588.2

x=3500

2. Two years: 20/( 1-5/6)= 120.

One year: 120-20= 100

( 120+ 100)/ 1 1/ 15=300

300- 100- 120=80

3、; 30x20/(30+20)= 12

4. The profit of Star Appliance Shopping Mall: 20/( 100-20)= 25%

Lianhua appliance store offers benefits:1-20% discount = 20%

People's Shopping Mall, the profit of all electrical appliances in this shopping mall: 10%-20%.

Xuanxingxing household appliance shopping mall

5、 10/ 1 1=0。 9 1

0。 More than 9 1 10% discount.

Xiaoming's mother went to another store and bought it at a "10% discount" store.