Question: How far north of the centre of Melbourne is the zoo where Queenie the elephant gave rides for children for 40 years located?

Related documents: [0]  [DOC] The Royal Melbourne Zoological Gardens, commonly known as the Melbourne Zoo, contains more than 320 animal species from Australia and around the world. The zoo is 4 km north of the centre of Melbourne. It is accessible via Royal Park station on the Upfield railway line, and is also accessible via tram routes 58 and 19, as well as by bicycle on the Capital City Trail. Bicycles are not allowed inside the zoo itself. [END] 
[1]  [DOC] Queenie was an elephant who was used to give rides for children at Melbourne Zoo for 40 years. [END]  
Answer: 4 km
4 km