Xiao Dong reads 4 / 5 of a story book in 12 days, and what is the average daily reading rate of this story book?
Daily = 4 / 5 ÷ 12=1/15
Xiao Ming has read 42 Pages of a story book, but there are still 58 pages left. What is the percentage of the total pages of the book?
The total number is 42 + 58 = 100 pages. After reading 42, it accounts for 21 out of 50