Answer:
16 Pages per day.
Explanation:
Total Pages of Book = 192
Number of days remaining to earn prize for completing the book = 12
Let x be the nomber of pages which she should read daily to fininsh book in 12 days; Hence
x = 192 / 12
x = 16
So if Stella will read 16 pages per day she will complete the book in 12 days and can earn the prize from media center.