Xiao Ming was reading a storybook. He had already read 40% of the book, and there were still 90 pages left. How many pages does this book have?
This book has a total of $90+ 40%$ $×$pages. Substituting 40% into the above formula: $90+04×$ $×$pages = $90+04×$ $×$ (100-90) = $90+04×$ $× $10 = $90+04×$ $× $100 = $90+40=130$pages Therefore, the book had a total of 130 pages.
Xiao Ming was reading a storybook. He had already read 40% of the book, and there were still 90 pages left. How many pages does this book have?
This book has a total of $90+40%<<20>>= 1620$pages. Of which, 40% of the pages were already read by Xiao Ming, and the remaining 90 +80=170 pages were unread.
Xiao Ming is reading a 150-page storybook. He has already read two-fifths of the book. How many pages are left?
Xiao Ming had already read two-fifths of a 150-page storybook, so he had already read 150 × 2/5 = 60 pages. Therefore, there were still 150 - 60 = 90 pages left in the storybook.
Zhang Ming was reading a storybook. He read 30 pages a day. After three days, there were still 8 pages of the book left. How many pages were there in this storybook?
Let's say this storybook has a total of $x$pages. According to the topic, 30 pages per day meant $30/div2 = 15$per hour. Zhang Ming read $15$pages per hour in $3$days so he read $3/30 = 90$pages in total. The remaining pages are $8/5 of the book, so there are: $$ 90 - \frac{8}{5} = \frac{16}{5} $$ Because the question requires the number of pages in the book, you need to multiply this result by $x$pages to get: $$ x \times \frac{16}{5} = \frac{16}{5} \times x = 96 $$ Solve this equation to get $x = 56$. So this story book had a total of $56$pages.
Naughty was reading a storybook. He had already read 5/7 of the total number of pages. There were still 40 pages left. How many pages were there in this storybook?
Let's say this storybook has a total of $x$pages. Naughty had finished reading $5/7$of the total page count, which meant that he had $2/7$left. Therefore, Naughty still needed to read $40$to finish the total number of pages. According to the meaning of the question, mischievous still needs to look at $40$pages, so $x - 40$should be divided by $7$. Since $x$is the total number of pages,$x$should be greater than or equal to $40$. Therefore, we can write an equation: $$x \geq 40 + 40 \times 7 = 560$$ The solution to this equation is $x=567$. So this story book had a total of $567$pages.
Xiao Ming was reading a 200-page storybook. He had already read two-fifths of the book and had 10 more pages. How many pages were left?
Xiao Ming had already read two-fifths of a 200-page storybook, which was 10 pages more. 200 pages × 2/5 + 10 pages = 40 pages The remaining pages were: 200 - 40 pages = 160 pages Therefore, Little Ming still had 160 pages left.
Xiao Lin was reading a book. He had already read 180 pages, and there were still 5/6 left. How many pages is this book?
This book had a total of 180 + 5/6 = 195 pages.
Huanhuan has already finished reading three-fifths of the total number of pages in the storybook. There are still 36 pages left. How many pages are there in this storybook?
The number of pages in a storybook can be expressed as $x$, so the total number of pages is $x \times 3/5$. Since there were still 36 pages to read, the total number of pages in the storybook plus these 36 pages was $x/times 3/5 + 36$. And because the book had a total of $x$pages, the equation could be listed: $$x \times 3/5 + 36 = x$$ If you solve this equation, you get $x=300$. Therefore, the story book had a total of $300$pages.
Xiao Lin was reading a 120-page storybook. He had already read 5/6 of it. How many pages are left?
Xiao Ming read a comic book. He had read 39 pages and there were still 52 pages left. How many pages did Xiao Ming read?
Xiao Ming read 39 pages and there were 52 pages that he did not read. The percentage of pages that Xiao Ming read in the total number of pages in this book is: 39 pages/52 pages = 7385% Therefore, the number of pages that Xiao Ming read accounted for 7385% of the total number of pages in the book.
Xiao Hua read a book and read 15 pages a day. After reading for 4 days, he still had 2/5 of the book left. How many pages of this storybook had he not read?
Assuming that this storybook had $x$pages, then the number of pages Little Light read every day was $15/div4 = 375$pages. Little Light had already read $4$for days, so the remaining pages were $x - 4/375 = x - 1125$. Because the number of pages Little Light reads every day is fixed, the number of pages can be expressed as: $$x - 4 \times 375 = 375 \times 4 - 1125$$ The above formula was simplified to: $$x = 48$$ Therefore, there were still $48 - 1125 = 3675 pages of this storybook that he had not read.