I am using MongoDB 3.0.10 with 10 databases in it,
also has implemented 3 member replica Set for it,
the question is it possible to replicate only selected databases from Primary to Secondary? If yes, then How?
You are basically looking for filtered replication, and as of writing this answer (August 2016) it is not available as a feature in MongoDB. The relevant feature request is SERVER-1559 for tracking/voting purposes (it is currently unscheduled).
In terms of options, you can get close to what you describe with the mongo-connector but that is not an officially supported tool.