Normal force(N) is always equal and opposite to the weight.
The floor is exerting an upward force upon the bag in order to support the weight of the bag.
Friction force is proportional to the normal force:
f = k N
In this case: f=27 N, k=0.23
27 N = 0.23 N
N= 27 N : 0.23 = 117.39 N
