Database
[{"_id":1,"questionDetail":{"answers":[{"srno":10,"userMatchPairAnswerCounts":[{"anssrno":8,"anscnt":0},{"anssrno":9,"anscnt":0}]},{"srno":20,"userMatchPairAnswerCounts":[{"anssrno":14,"anscnt":0},{"anssrno":15,"anscnt":0},{"anssrno":16,"anscnt":0}]}]}}]
Query
db.collection.update({"_id":1,"questionDetail.answers.srno":10},{"$inc":{"questionDetail.answers.$[answer].userMatchPairAnswerCounts.$[userMtc].anscnt":1}},{arrayFilters:[{"answer.srno":10},{"userMtc.anssrno":9}]})