To determine who will finish reading their book first, second, and third, we need to calculate the number of pages each friend reads per day and then use that information to calculate how many total days it will take each friend to finish their book.
Barbara:
Barbara read 100 pages in 4 days, so she reads 100 / 4 = 25 pages per day.
Barbara's book has 320 pages, so it will take her 320 / 25 = 12.8 days to finish the book.
Judy:
Judy read 54 pages in 3 days, so she reads 54 / 3 = 18 pages per day.
Judy's book has 260 pages, so it will take her 260 / 18 = 14.44 days to finish the book.
Nancy:
Nancy read 160 pages in 5 days, so she reads 160 / 5 = 32 pages per day.
Nancy's book has 480 pages, so it will take her 480 / 32 = 15 days to finish the book.
Therefore, Barbara will finish reading her book first, Judy will finish second, and Nancy will finish last.