Jayden has been reading a 275-page book for English class. On average, he has read about 10 pages in 15 minutes .With a deadline looming, Jayden realizes that he won't finish in time unless he skims through the rest of the book. If he skims the book, he can cover 15 pages in 10 minutes. If it takes Jayden 5 hours and 50min, to finish the book (reading and skimming combined), how many pages did Jayden have to skim through?