If 30 is half the number of her spots, then she has 30*2=<<30*2=60>>60 spots total.
If one-third of her spots are located on her back and hindquarters, then she has 60/3=<<60/3=20>>20 spots located on her back and hindquarters.
If the reaming spots are located on her sides, then 60-30-20=<<60-30-20=10>>10 spots are located on her sides.
#### 10