Let the number of chairs Gavin build per week is x and number of tables he builds per week is y.
It takes 4 hours to work on a chair and 10 hours to work on a table. So time taken to work on x chairs and y tables will be:
[tex]Time=4x+10y[/tex]
Gavin wants to work for no more than 40 hours. So we can write the inequality as:
[tex]4x+10y \leq 40[/tex]
It takes $10 worth of supplies to build a chair and $15 worth of supplies to build a table. So cost or worth of supplies for x chairs and y tables will be:
[tex]Cost=10x+15y[/tex]
Gavin wants to spend no more than $80 on material. So we can write the inequality as:
[tex]10x+15y \leq 80[/tex]
Thus the system of inequalities is:
[tex]4x+10y \leq 40[/tex]
[tex]10x+15y \leq 80[/tex]
We can observe the possible combinations from the graph of these inequalities, which is shown below:
a) 0 chair and 3 tables
b) 5 chairs and 2 tables
c) 8 chairs and 2 tables