Can you figure out the answer to the fourth equation?
The way to solve this is to figure out what numbers the symbols represent.
Start with the first equation: three shoe symbols added together equals 30, meaning that the shoe symbol represents the number 10.
Then 10 + C + C = 20, so each cat represents the number 5.
Watch out though — not all of the cats are the same.
You can read a full explanation of how to solve the riddle from Reader's Digest here.
This, Ladies and gentleman, this is the reason why smart people can pretend to be stupid, but stupid people can never successfully pretend to be smart.
PS: the person that made the image did not understood the riddle.