[{"_id":ObjectId("5d4104820c0d131f88e10141"),"ModifiedOn":ISODate("2019-07-31T03:01:23.01Z"),"name":"Wet Paint","funding_rounds":[{"raised_amount":NumberInt("100")},{"raised_amount":NumberInt("100")}]}]

db.collection.aggregate([{"$match":{"funding_rounds.0":{"$exists":true}}},{"$project":{"total_rounds":{"$size":"$funding_rounds"},"name":"$name","Average_amount_raised":{"$avg":"$funding_rounds.raised_amount"},"_id":0}},{"$sort":{"Average_amount_raised":-1}}])