Once he transforms from his puny human form, how much does the Incredible Hulk weigh?


Question: XPATH Selecting by position returns incoherent results
Answer: Put //pregunta in parenthesis. Change your XPath expressions to (//pregunta)[1]/@id, (//pregunta)[2]/@id ...

Without parenthesis e.g. //pregunta[4] evaluates to all pregunta elements which are at the fourth position of their parent element. 

However (//pregunta)[4] first calculates the sequence of all pregunta elements and then takes the fourth element of that sequence.