Respuesta :

Roughly a little over 60 doses. The reason is if you take two more 4oz bottles making it 12oz you get 60 doses.  
65 doses!! Simple math:
4*y=13  
4*3=12+1.  4/4=1
20/4 = 5 so 5=1 so y=5
3*20 = 60
60+5=65
Hope that helped!!