Hi!
Book has 481 pages, and she read 481 - 403 = 78 pages in 1,5 hours. We can calculate the rate in pages per hour like this:
78 pages in 1,5 hours
x pages in 1 hour
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x = (78*1)/1,5
x = 78/1,5
x = 52
Shryia reads 52 pages per hour.
To find how long did it take her to read the entire book, we will divide the number of pages in the book by the rate of pages read in one hour, like this:
481/52 = 9,25
It took her 9,25 hours to read the entire book.
Hope this helps!