## Beibei read a 120 page story book. On the first day, she read 2 / 5 of the whole book, and on the second day, she read the remaining 5 / 9. How many pages did Beibei read the next day?

120 * (1-2 / 5) * 5 / 9 = 120 / 3 = 40 pages

Xiao Lan read a story book. On the first day, she read one sixth of it, and on the second day, she read 42 Pages. This is the ratio of the pages she has read to the pages she has not read. It's 2:3. How many pages are there in the book?

There must be a formula for solving~~~~~~~~

This is the ratio of the number of pages that have been seen to the number of pages that have not been seen, which is 2:3

So I've seen two fifths

42 / (2 / 5-1 / 6) = 42 / (7 / 30) = 180 pages

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