. The sides of a whiteboard are 1 foot by 1 foot. How many 2 inch by 2 inch Post-it notes
will be needed to cover the entire whiteboard?
18
36
727
18
36
72

One drawback of voluntary trade is that it a. requires two groups to use a common language b. can make one group dependent upon another for necessary goods c. doesn't occur unless there is a shortage of goods for at least one group d. forces groups to rely on themselves to produce all the goods they need