Answer:
(a)The optimal bundle is Rental = 3 and Coffee = 2
(b)Rental = 6 and Coffee = 2
(c)They are both the goods are normal
Step-by-step explanation:
(a)The optimal bundle is Rental = 3 and Coffee = 2
The Langrangian formula for solving utilization problem is stated as:

where 16=4R+2C is the consumer budget limit.
Using differentiation forthe Lagrangian formula with R and C, we will get

To solve Equation 3 and the budget limit =
R=3 and C=2
(b)Rental = 6 and Coffee = 2
In order for us to solve the substitution effect. we shall calculate the income at which the initial bundle is affordable.
which is =

- Substitution effect :R -R = 3.75- 3 = 0.75 and C' - C = 1.25 - 2 = -0.75
- Total effect = R - R = 6-3 = 3 and C- C = 0
- Income effect = total effect - substitution effect
(c)They are both the goods are normal
The demand for rental and coffee is given as
. The increase in income also increases the demand for rental and coffee. So, they two goods are both normal.