You would buy the set of four postcards 4 times. This would equal $4 for 12 postcards. Then you would have to buy 3 individual postcards. Those 3 postcards would be $1.50 $4+$1.50=$5.50
Step-by-step explanation: <em>Divide 2 by 16 to get how many hours it takes to run 1 mile. Then multiply that number by 40 to get how many hours it would take run 40 miles.</em>