Xiao Min reads a book, reading six pages on the first day, and then reading four more pages every day than the day before. After reading for three days, he only read three-eighths of the book, so he kept reading. Pages that can be read in three days in at least (6) days = 6+(6+4)+(6+4x2) = 6x3+4x (1+2) =18+12 = 30 pages. This book has * * 30 pages. 8= 80 pages left =80-30= 50 pages read on the fourth day =6+4x3= 18; 6+4x4=22 on the sixth day; 6+4x5=26 on the fourth, fifth and sixth days; * * = 18.