Yeah I also wondered if it was a trick question in the sense they do some ad hoc pedantic interpretation of the words. Because taking it at face value its so easy that I wondered how people could missed it. But alas its just a super easy problem.
I love trick questions. One of my favorites, which needs to be told, goes like this:
An empty bus (except for the driver) pulls up to the first stop. Two people get on. At the next stop, six people get on. Then eight peolpe get on, and two get off. Then seven people get on. At the next stop, three get on, and five get off. At the next stop, Three get on and one gets off.
Question: How many stops did it make?
Very rare than anyone gets the right answer.