In my town, 10% of the dogs think they are cats and 10% of the cats think they are dogs. One day I tested all the 160 cats and dogs in the town and found that 20% of them thought they were cats. How many of the 160 animals were cats?

Answer 1

32 thought they were cats.
so, assuming that those cats who did not think they were dogs, really are cats, and there are c cats,
0.9c + 0.1(160-c) = 32
c=20.
so there were 140 dogs.
check:
14+18 = 32