Which of the following is an extensive property of water?

Extensive properties depend on the amount of substance. The volume of a sample is an extensive property: 1000 grams of water takes up more volume than 10 grams of water. Mass is also an extensive property.

So what you would do is go through and add 3 teaspoons(tsp) 6 times because of the 6 tablespoons(tbsp). which will give you an answer of 18. another way is to multiply 3x6=18.