Analysis: If the price is increased by X yuan, the unit price of purchase is 50 yuan, and each piece is sold in 60 yuan, 800 pieces can be sold; if each piece is sold in 0 yuan, the price is increased by 65,438 yuan, and its sales volume will be reduced by 20 pieces. Now, if the profit is 65438 yuan +02000 yuan, the equation can be listed and solved. If the sales cost is not more than 24000 yuan, you can know how many clothes you should buy, and the sales cost is not less than 24000 yuan.

Solution: Suppose the price of this kind of clothing has increased by X yuan.

Judging from the meaning of the question: (60-50+x)(800-20x)= 12000.

Solve this equation: x 1= 10, x2 = 20.

When x 1= 10, 800-20× 10=600, 50× 600 = 30,000 > 24,000, it is discarded;

∴x=20,800-20×20=400,60+20=80

A: The unit price of this kind of clothing should be determined as 80 yuan. At this time, 400 clothes will be imported.

It is very important to analyze the application problem, find out the equivalence relation, solve the equation, and finally pay attention to the given constraints and practical significance of the problem to verify the results!

I hope it inspires you. If you still don't understand, you can ask me or trust me privately!