⑵ If it is set to computer Y, it is set to computer B (15-Y) to get the inequality group.
3800Y+3000( 15-Y)≥48000
3800Y+3000( 15-Y)≤50000
The solution is Y≥3.75 and Y≤6.25, because y is a positive integer, ∴ y = 4,5,6.
∴ * * There are three purchase schemes:
A enters 4 sets, and B enters 1 1 set;
A into 5 sets, B into 10 sets;
A into 6 units, B into 9 units;
(3) A earns 500 yuan for each set, and B earns 800 yuan for each set.
Scheme 1: A enters 4 sets and B enters 1 1 set, earning 4× 500+11× 800 =10800.
Scheme 2: A enters 5 sets and B enters 10 sets, earning 5× 500+10× 800 =10500.
Scheme 3: A enters 6 sets and B enters 9 sets, earning 6×500+9×800= 10200.
According to the topic:10800-11a =10500-10a =10200-9a,
A=300, that is to say, each B computer only earns money from one computer.
The title requires that in order to open up the market, the more computers B sell, the better, so the first scheme is adopted.