2000A+4000B+ 1000C≥80000
A+B+C≥30 (people who are less than these times are twice as unwilling to see it happen as those who are more than these times; This sentence should have this meaning)
40A+60B+80C≤2400；
a≥C；
B≥C .
The next step is to solve the problem. Drawing on the number axis leads to the linear programming problem.
The first priority on the first floor is that the cost is at least inconsistent with the meaning of the topic. People pay the highest attention to achieving the advertising effect, that is, the people who listen to it are the most. )