Traditional Culture Encyclopedia - Weather inquiry - The weather in Chongqing suddenly turned cold. In order to seize the opportunity of selling down jackets, the mall decided to buy 500 down jackets of three brands, A, B and C, for 235,000 yuan.

The weather in Chongqing suddenly turned cold. In order to seize the opportunity of selling down jackets, the mall decided to buy 500 down jackets of three brands, A, B and C, for 235,000 yuan.

(1) The number of C brand down jackets is 500-x-y (or 47-45x-110y);

(2) From the meaning of the problem:

400 x+550y+500(500 x-y)= 235000

Finishing: y = 2x-300;;

(3)①P =(500-400)x+(800-550)y+(650-500)(500-x-y)-2000,

And y = 2x-300,

∴ Sorting: P= 150x+43000

② The quantity of C brand down jackets purchased is:

500 x-y = 500 x-(2x-300)= 800-3x

According to the meaning of the problem, list the inequality groups.

x≥ 1002x? 300≥ 100800? 3x≥ 100,

Solution: 200≤x≤7003

The range of ∴x is 200≤x≤x7003,

X is an integer, and the maximum value of X is 233.

∫ in P= 150x+43000, k = 150 > 0,

∴P increases with the increase of X.

When the maximum value of x is 233, the maximum value of p is 77950 yuan.

At this time, 233 sets of A, B and C brand down jackets were purchased, which were 166 sets and10/set respectively.