It is understood that Red Star Building Materials Store sells a kind of building materials for a factory (consignment here means that the manufacturer provides the goods for free first, and then settl

It is understood that Red Star Building Materials Store sells a kind of building materials for a factory (consignment here means that the manufacturer provides the goods for free first, and then settles the accounts after the goods are sold. (1) When the price per ton is 240 yuan, the monthly sales volume at this time is 60 tons;

(2)y=﹣x 2 +3 15x﹣24000；

(3) In order to obtain the maximum monthly profit, the sales price should be set at 2 10 yuan per ton;

(4) Xiao Jing is wrong See explanation.

Test and analysis: this question belongs to marketing, and the monthly profit = (price per ton-other expenses per ton) × sales volume. The relationship between sales volume and selling price per ton should be clearly expressed, and then the problem of profit maximization should be solved by using the properties of quadratic function.

Problem analysis: (1) From the meaning of the question:

45+ ×7.5=60 (ton);

(2) According to the meaning of the question:

y=(x﹣ 100)(45+ ×7.5)，

Simplified: y = ﹣ x 2+315x ﹣ 24000;

(3)y=﹣x 2+3 15x﹣24000=﹣(x﹣2 10)2+9075。

In order to obtain the maximum monthly profit, the material price should be set at 2 10 yuan per ton;

In my opinion, Xiao Jing is wrong.

Reason: When the monthly profit is maximum, X is 2 10 yuan.

For monthly sales w = x (45 +× 7.5) = (x+160) 2+19200,

When x is 160 yuan, the monthly sales volume w is the largest.

When x is 2 10 yuan, the monthly sales volume w is not the largest.

Xiao Jing is wrong.