[{"_id":ObjectId("111e2133c57a1d6111111111"),"scores":[{"date":ISODate("2021-03-29T05:00:20.965Z"),"test 1 points":50,"test 2 points":10,"total possible points":100}]},{"_id":ObjectId("111e2133c57a1d6111111222"),"scores":[{"date":ISODate("2021-03-27T05:00:20.965Z"),"test 1 points":30,"test 2 points":20,"total possible points":200}]},{"_id":ObjectId("111e2133c57a1d6111111223"),"scores":[{"date":ISODate("2021-03-27T05:00:20.965Z"),"test 1 points":10,"test 2 points":30,"total possible points":200}]}]

db.collection.aggregate([{$unwind:"$scores"},{$addFields:{validEntry:{$gt:[{$divide:[{$add:["$scores.test 1 points","$scores.test 2 points"]},"$scores.total possible points"]},0.5]}}},{$match:{validEntry:true}},{$group:{_id:"_id",scores:{$push:"$scores"}}}])