db={"Result":[{_id:ObjectId("6010664ac5c4f77f26f5d005"),questions:[{_id:ObjectId("5d2627c94bb703bfcc910763"),correct:false},{_id:ObjectId("5d2627c94bb703bfcc910764"),correct:true},{_id:ObjectId("5d2627c94bb703bfcc910765"),correct:true}]},{_id:ObjectId("6010664ac5c4f77f26f5d006"),questions:[{_id:ObjectId("5d2627c94bb703bfcc910763"),correct:false},{_id:ObjectId("5d2627c94bb703bfcc910764"),correct:false},{_id:ObjectId("5d2627c94bb703bfcc910766"),correct:true}]},{_id:ObjectId("6010664ac5c4f77f26f5d007"),questions:[{_id:ObjectId("5d2627c94bb703bfcc910764"),correct:false},{_id:ObjectId("5d2627c94bb703bfcc910765"),correct:true},{_id:ObjectId("5d2627c94bb703bfcc910766"),correct:true},{_id:ObjectId("5d2627c94bb703bfcc910764"),correct:true}]}],"Question":[{_id:ObjectId("5d2627c94bb703bfcc910763")},{_id:ObjectId("5d2627c94bb703bfcc910764")},{_id:ObjectId("5d2627c94bb703bfcc910765")},{_id:ObjectId("5d2627c94bb703bfcc910766")},{_id:ObjectId("5d2627c94bb703bfcc910767")}]}

db.Result.aggregate([{"$unwind":"$questions"},{"$group":{"_id":"$questions._id","correct":{"$push":"$questions.correct"}}},{"$project":{"newField":{"correctAnswers":{"$size":{"$filter":{"input":"$correct","as":"bool","cond":"$$bool"}}},"wrongAnswers":{"$size":{"$filter":{"input":"$correct","as":"bool","cond":{"$not":"$$bool"}}}}}}}])