Final answer:
To find the percent of last semester's college costs spent on books, divide the amount spent on books by the total cost and multiply by 100. The answer is 14%.
Step-by-step explanation:
To find the percent of last semester's college costs that was spent on books, we need to divide the amount spent on books ($392) by the total cost of last semester ($2800) and then multiply by 100.
Percent spent on books = (Amount spent on books / Total cost of last semester) * 100
Percent spent on books = (392 / 2800) * 100 = 14%
Therefore, 14% of last semester's college costs was spent on books.