Question

Jimmy's mother had four children one named april second named may what was the name of the third child?

Answer 1

<<I think there is a mistake in the question. The statement should read Jimmy’s mother had three children (not four as mentioned). The question is answered on this basis.>>

The answer is Jimmy.

The name of the third child is Jimmy.

Explanation:

The opening sentence itself has the answer. It says “Jimmy’s mother”. So, Jimmy is one of the mother’s children. If among her three children, April and May are two children, then the third child must be Jimmy.

Alternatively, if the question is right as it is, we can assume that the third child is June based on the sequence followed. In that case, Jimmy will be the name of the fourth child.

Answer 2

The first two words "JIMMY'S mother" states that the person who would be stated in the rest of the sentence is the mother of Jimmy. 

So obviously, Jimmy has to be the son of his mother.
Further on reading the question we incur three more persons named Monday, Tuesday and Wednesday. So if one, does not read the question carefully he/she might name the fourth child to be Thursday (Week days).

But, since we are to answer seriously we stress on the two words "Jimmy's mother" which makes it logical that the three persons talked are his siblings.

And further, Jimmy along with his siblings make the statement "had four children" true. Hence , the fourth child is referred to Jimmy.