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A mathematical application problem with seven strokes (inequality group)
Solution: (1) Let each photo album be X yuan and each cultural shirt be (x+9) yuan.

5x+2(x+9)=200

X=26 x+9=26+9=35。

A: Every photo album 26 yuan, every T-shirt 35 yuan.

(2) Buy M T-shirts and 50m photo albums.

1800—[35m+26 (50m) ]≥270 ①

1800—[35m+26 (50m) ]≤300 ②

To ①m≤230/9

(2) M≥200/9

So the solution set of inequality group is: 200/9≤m≤230/9.

∵m can only be a positive integer. The solution satisfying the condition is: m=23, 24, 25.

Therefore, * * * has three purchase schemes: scheme 1: buy 23 cultural shirts and 27 photo albums;

Option 2: buy 24 cultural shirts and 26 photo albums; Option 3: Buy 25 T-shirts and 25 photo albums.

Suppose that the fund for purchasing teachers' souvenirs is Y yuan.

Y =1800—[35m+26 (50m)] = 500-9m.

∵k=-9 ∴ According to the properties of linear functions, y decreases with the increase of m.

Therefore, when m=23, the funds for purchasing teachers' souvenirs are the most abundant. So choose option one.