The solution to HOMEWORK 4.1 M101JS: MongoDB for Node.js Developers

The solution to HOMEWORK 4.1 M101JS: MongoDB FOR NODE.JS DEVELOPERS

Suppose you have a collection with the following indexes:

> db.products.getIndexes()
[
	{
		"v" : 1,
		"key" : {
			"_id" : 1
		},
		"ns" : "store.products",
		"name" : "_id_"
	},
	{
		"v" : 1,
		"key" : {
			"sku" : 1
		},
                "unique" : true,
		"ns" : "store.products",
		"name" : "sku_1"
	},
	{
		"v" : 1,
		"key" : {
			"price" : -1
		},
		"ns" : "store.products",
		"name" : "price_-1"
	},
	{
		"v" : 1,
		"key" : {
			"description" : 1
		},
		"ns" : "store.products",
		"name" : "description_1"
	},
	{
		"v" : 1,
		"key" : {
			"category" : 1,
			"brand" : 1
		},
		"ns" : "store.products",
		"name" : "category_1_brand_1"
	},
	{
		"v" : 1,
		"key" : {
			"reviews.author" : 1
		},
		"ns" : "store.products",
		"name" : "reviews.author_1"
	}

Which of the following queries can utilize at least one index to find all matching documents or to sort? Check all that apply.

Solutions:
db.products.find( { 'brand' : "GE" } ).sort( { price : 1 } )
db.products.find( { $and : [ { price : { $gt : 30 } },{ price : { $lt : 50 } } ] } ).sort( { brand : 1 } )

I have submitted those two answers and found it to be correct.
Let me know if you have any problems.