A. B two shopping malls usually sell the same goods at the same price. During the Spring Festival, all goods in a shopping mall are sold at a 20% discount. After spending more than 200 yuan in B shopping mall, you can shop at this shopping mall at a 70% discount. How to choose a shopping mall to shop more economically? I set up the equations as follows: y=(x-200)X7/10+200 ① y=8/10x ② The solution is x = 600, substituting ① = 280, substituting ② = 480? Right, isn't it all = 0?

A. B two shopping malls usually sell the same goods at the same price. During the Spring Festival, all goods in a shopping mall are sold at a 20% discount. After spending more than 200 yuan in B shopping mall, you can shop at this shopping mall at a 70% discount. How to choose a shopping mall to shop more economically? I set up the equations as follows: y=(x-200)X7/10+200 ① y=8/10x ② The solution is x = 600, substituting ① = 280, substituting ② = 480? Right, isn't it all = 0?

If the total amount of purchase is X Yuan and the actual consumption is y yuan, then if x ≥ a, it will be cheaper (A-200) × 0.7 + 200 ≤ a × 0.8 to spend 200 in shopping mall B. the solution is: a ≥ 12000 / 7 ≈ 1714.29, that is, the most economical way of shopping is: when the amount of purchase is not more than 1714.29 yuan, when a

Guangming shopping mall will increase the price of a commodity by 60% and then price it. When selling, it will first give 10% discount and then make a profit of 28 yuan. In this way, each item will make a profit of 30%. How much is the price

Set purchase price X Yuan
X*(1+60%)*0.9-28=X*(1+30%)
1.44X-28=1.3X
0.14X=28
X=28/0.14
X=200
The purchase price is 200 yuan

A store will increase the purchase price of a suit by 30% as the retail price, and each suit will be priced at 780 yuan. During the new year's day, the store will sell the suit at a 10% discount,
As a result, 10 suits will be sold in one day. How much will the suit of this brand make a profit on that day?

Suppose the purchase price is 780x100 / 130 = 7800 / 13, the new year's day price is 780-78 = 702, the profit of each piece is 702-7800 / 13 = 102, and the profit of 10 pieces is 1020. I don't know if it is correct