Question: How many rivers end in the Indian Ocean?
SPARQL:
SELECT DISTINCT COUNT(?uri) WHERE {?uri <http://dbpedia.org/ontology/riverMouth> <http://dbpedia.org/resource/Indian_Ocean>  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/River>}