A peddler went to a vegetable stall to buy cucumbers. He bought 30 Jin this morning, and the price is X yuan per Jin. In the afternoon, he bought another 20 Jin at the price of Y yuan per Jin. Later, after he sold it at the price of x+y2 yuan per catty, he found it was a loss. The reason is ()

A.xy C.x≤y D.x≥y

According to the question, the average cucumber he bought was 30x+20y50 per catty.

After selling at the price of x+y2 yuan per catty, I found myself losing money.

Then 30x+20y50 > x+y2.

Solution, x > y.

So the reason for losing money is x > y.

So choose B.

In response to the policy of benefiting farmers by "home appliances going to the countryside", a shopping mall decided to buy 80 refrigerators of three different models from manufacturers, of which the number of type A refrigerators was twice that of type B refrigerators, and the total purchase amount of three refrigerators did not exceed132,000 yuan. It is known that the ex-factory price of type A, B and C refrigerators is1.each refrigerator in 200 yuan.

(1) How many refrigerators have you bought at least?

(2) If the number of Class A refrigerators is required not to exceed the number of Class C refrigerators, what are the procurement plans?

Solution: (1) If you buy X B refrigerators, you will buy 2 A refrigerators and 80-3 C refrigerators.

According to the meaning of the question,1200× 2x+1600x+(80-3x )× 2000 ≤132000.

X≥ 14 for solving this inequality.

∴ Buy at least 14 type B refrigerators;

(2) According to the meaning of the question, 2x≤80-3x.

X≤ 16 for solving this inequality.

It is known from (1) that x≥ 14.

∴ 14≤x≤ 16

And ∵x is a positive integer

∴x= 14, 15, 16.

So, there are three purchase schemes.

Scheme 1: There are 28 Class A refrigerators, 28 Class B refrigerators 14 refrigerators and 38 Class C refrigerators.

Scheme 2: 30 Class A refrigerators, 35 Class B refrigerators 15 refrigerators and 35 Class C refrigerators.

Scheme 3: 32 Class A refrigerators, 32 Class B refrigerators 16 refrigerators and 32 Class C refrigerators.