Answer:
Substitution Effect outweighs Income Effect ; Labour Supply Curve between wages will be upward sloping. OR :-
Income Effect outweighs Substitution Effect ; Labour Supply Curve between wages will be backward bending
Explanation:
Relationship between wage rate & labour supply can be explained by two effects :
Wage rate change from $20 to $25 is a case of wage rate increase
If substitution effect > income effect, labour supply would increase as a result of wage rise ( from $20 to $25). So, the labour supply curve would be upward sloping
If income effect > substitution effect, labour supply would decrease as a result of wage rise ( from $20 to $25). So, the labour supply curve would be backward bending