Explanation:
This is an example of a linear programming problem.
THE CONSTRAINTS
Let d, c represents number of desk and chair.
Marketing restrictions
c ≥ 2d; which can be written as
2d - c ≤0
Wood restriction
4d + 3c ≤ 20
OBJECTIVE FUCTION (MAX)
= 40d + 25c
Where d ≥ 0, c ≥ 0
With this details you can then find the solutions either graphically or using any other linear programming solution methods.