Answer:
43,000 Citizens
Step-by-step explanation:
Data
Hamster   8%
Fish      12%
Dogs  23%
Sum     43%
The total population is 100,000 citizens. To find the number of citizens for each pet obtain the percentage of 100,000:
Citizens who chose hamsters are  8% of 100,000
100,000*8/100=8,000
Citizens who chose fish are  12% of 100,000
100,000*12/100=12,000
Citizens who chose dogs are  23% of 100,000
100,000*23/100=23,000
Citizens who choose hamsters, fish or dogs, is the sum of these three results
8,000+12,000+23,000=43,000