Jread 147 pages in a book. he has completed 70% of the book. how many more pages does he need to read to finish the book.

147/x=100/70 (147=100, 70 is from the percent)
(147/x)*x=(100/70)*x
147=1.4285714285714*x
147/1.4285714285714=x
x=102.9 is your answer