If Xiaoming reads a storybook, he reads 38 pages in the first 2 days and 54 pages in the next 3 days. How many pages does Xiaoming read on average every day?Xiao Ming read a story book and read a total of 38 pages in the first two days and 54 pages in the next three days. We can use the total number of pages to deduct the number of pages in the first two days and the next three days to get the average number of pages that Xiaoming reads every day.
Total pages = 38 + 54 = 82
In the previous two days, he had read 38 pages, so the ratio of the number of pages read in the previous two days to the total number of pages was 38 pages/ 82 pages = 047875, which could be approximately expressed as 047875.
In the next three days, a total of 54 pages were read. The ratio of the number of pages read in the next three days to the total number of pages was 54 pages/ 82 pages = 06667, which could be approximately expressed as 06667.
Therefore, on average, Xiaoming reads 047875 × 2 + 06667 × 3 = 016533 × 2 + 023333 × 3 = 039167 × 2 + 050938 × 3 = 089715 × 2 + 010785 × 3 = 1575 × 2 + 0192 × 3 = 27533 every day, which is about 275.
Therefore, Xiao Ming read an average of 275 pages a day.
When Teacher Zhang reads a book, he reads an average of 20 pages a day for the first 4 days, and 63 pages in total for the next 7 days. He just finishes reading this book. How many pages does Teacher Zhang read on average every day?Assuming that the book has a total of n pages, then Teacher Zhang has read 20×4=80 pages in the past four days, leaving n-80 pages.
In the next 7 days, he read 63 pages, so the remaining pages were 63-80=-3 pages. This result is negative, which is not consistent with reality, so there is a contradiction in the hypothesis.
Therefore, this problem is not solved. Teacher Zhang reads an average of 80 pages a day, but he has read 20 pages in the past four days, so he still needs to read another 40 pages to finish the book.