Hello everyone, I have a problem with this other linear programming problem:

In a large hospital, surgical operations are classified into 3 categories according to their average duration 30 min, 1 hour and 2 hours. The hospital receives a fee of $ 100, $ 150 and $ 200 for an operation in categories 1, 2 and 3 respectively. If the hospital has 8 operating rooms which are used an average of 10 hours per day, How many transactions can be programmed so that, a):maximize the incoming money, b) maximizes the number of operations?

SOLUTION:

a) maximize z = 100x1 + 150x2 + 200x3. Restriction  0'5x_1+x_2+2x_3\leq 80.

Function to maximize z=x_1+x_2+x_3 , Restriction: 0'5x_1+x_2+2x_3\leq 80,\;x_i\geq{0}

but my teacher seems to be poorly resolved, because apparently lack an equation ... I do not think most are missing it?

Suddenly, thinking, I thought that the other equation must be of the form
x_1 + x_2 + x_3 \leq{} a given number of operations,


but I am not clear, any idea anyone?

But if that's OK, what would be the dual of this problem?

A greeting and thank you very much