Answer
Domain=[80, 100] ie. both of them inclusive.
Explanation:
Albert has total $105.
Let the cost of a product be c.
Therefore, the total cost of a product after the delivery and all is represented by a function f(c)
f(c)=c+
![(c)/(20)](https://img.qammunity.org/2020/formulas/mathematics/high-school/q6tk4i2oxv3z8qflt7l5l1m0i74bs3lww0.png)
f(c)=
![(21c)/(20)](https://img.qammunity.org/2020/formulas/mathematics/high-school/g8xxa6lqct2d2q4ocon33icr1xq6mbk8oq.png)
The domain, of the function is the no. of possible values of c that can satisfy the equation.
Now, lets check the maximum price of the product that Albert can buy.
f(c)=105
=105
c=$100
As, the minimum price of a product of is $80 , the domain needs to start from here. And it will go on till $100.
Domain=[80, 100]