Xiaowen had read two-fifths of the book, which meant that Xiaowen had read 2/5 * 170 = 48 pages.
Therefore, there were still 170 - 48 = 122 pages that he had not read.
Suppose the book has x pages.
On the first day, he read two-fifths of the book, which was 2/5x pages.
The next day, he read a quarter of the book, which was x/4 pages.
Because there were still 70 pages left, there were:
2/5x + x/4 - 70 = 0
To simplify it:
5x/4 - 70 = 0
Solution:
x = 400
Therefore, the book had a total of 400 pages.
Assuming that the book has x pages, then Little Light has read 2/5x pages. Because Little Light counted 80 pages, there were:
2/5x + 80 = x
Solve the equation:
x = 50
Therefore, the book had a total of 50 pages.
If Xiao Hong had already read 40 pages of a book, which was two-fifths of the book, then Xiao Hong had already read 20% or 0.2 times the book.
How many pages are there in the book? You can divide the number of pages by the number of pages in the book:
(100% - 02) / 100% = 90%
Therefore, Little Red only had 10 pages left.
This book had:
39 + 2/5 = 39 + 06 = 406 pages.
Because the number of pages in a book must be an entire number, the decimals needed to be rounded to the nearest whole number. Therefore, the book had a total of 40 pages.
Suppose the book has x pages.
On the first day, he read a quarter of the book, which was 1/4 * x page of the book.
The next day, he read two-fifths of the book, which was 1/4 * x pages, 2/5 = 5/16 * x pages.
There were still 14 pages left, so:
14 ÷ (5/16 * x - 1/4 * x) = 14/(1/4 * x - 1/4 * x) = 14/(1/16 * x - 1/16 * x) = 14/(5/8 * x) = 14/(1/8 * x)
To simplify it:
14/(1/8 * x) = 14
So 8 * 14 = x
Solution:x = 96
So this book had a total of 96 pages.
Xiao Ming had already read two-fifths of a 30-page book, so there were 30 - 2/5 = 30 - 04 = 296 pages left.
Therefore, there were 296 pages left in the book.
Xiaowen had read two-fifths of the book, which meant that Xiaowen had read 170 pages divided by 2 = 85 pages.
There were still 170 - 85 pages = 85 pages that he had not read.
Suppose the book has x pages:
Little Cong read 15 pages a day for four days, a total of 4×15=60 pages.
The total number of pages in the book is x, so:
60÷(1+3/5)=x÷5
The solution was:x=60×5 div3 =600 div3 =200 pages.
Therefore, the book had a total of 200 pages.