There are two possibilities for this question:
1- The shopping cart is at rest (not moving):
In this case:
∑Forces = 0
Force exerted by Jim + Force exerted by cart = 0
2 + Force exerted by cart = 0
Force exerted by cart = -2
2- The cart is moving as a result of a net force "m":
In this case:
∑Forces = m
Force exerted by Jim + Force exerted by cart = m
Force exerted by cart = m-2