Pack A has 6 notebooks for 8.40 dollars. Pack B has 10 notebooks for 13.50 dollars. Which is the better buy if the notebooks are identical?
Explanation
Pack A costs 1.40 dollars per notebook, while Pack B costs 1.35 dollars per notebook, so Pack B gives the lower unit price. Choosing Pack A only because 8.40 dollars is the lower total price ignores that it contains fewer notebooks.