these kinds of and this kind of - which one is right?
Which sentence is right?

these kinds of mistakes
these kind of mistakes
this kind of mistakes

Question

these kinds of and this kind of - which one is right?
Which sentence is right?

these kinds of mistakes
these kind   of mistakes 
   this kind   of mistakes

Answer

Singular would be "this kind of mistake" -referring to one type of mistake
Plural would be "these kinds of mistakes" -referring to multiple mistakes

Hope that helps!