Class C refrigerator (80-2x), list the inequalities according to the meaning of the question:
1200 * 2x+ 1600 x+2000 *(80-3x)≤ 13200
Solve this inequality and get. x ≥ 14。
Buy at least 14 type B refrigerators.
(2) According to the meaning of the question, get 2x ≤ 80-3x.
Solve this inequality and get. x ≤ 16。
It is known from (1) that x ≥ 14.
∴ 14≤x≤ 16
X is also a positive integer,
Therefore, there are three purchase schemes:
Scheme 1: 28 Class A refrigerators, 2 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.