the demand for a candy bar is expressed by the function:
Qd=5450-2000P-0.1R+1000Pc
Qd represents the number oF candy bar demanded,
P represents the preice of candy bar,
R represents consumer average montly income ,
P represents the price of chocolate a related produce
1- Illustrate what can we conclude about the income elasticity of demand?is it positive or negative?what class of goods candy bar belongs to?