Xiaoqiang read a book, read 2 / 15 of the whole book every day, read a total of 84 pages in 7 days. How many pages are there in this book? Xiaoqiang read a book every day. He read a total of 84 pages in seven days. How many pages is the book? 15

Xiaoqiang read a book, read 2 / 15 of the whole book every day, read a total of 84 pages in 7 days. How many pages are there in this book? Xiaoqiang read a book every day. He read a total of 84 pages in seven days. How many pages is the book? 15

84 / 7 / 2 / 15 = 14 / 2 / 15 = 105 pages a: there are 105 pages in this book

Last year, Xiao Ming was 28 years younger than his father. This year, his father's age is eight times that of Xiao Ming. How old is Xiao Ming this year?

Xiaoming's age: 28 ^ (8-1), = 28 ^ (7), = 4 (years old). A: Xiaoming is 4 years old

Xiaojun is 8 years old and his father is 34 years old. When Xiaojun was 3 years old, his father was 3 times as old as Xiaojun

After X years, my father's age is three times that of Xiaojun
3*(8+X)=34+X
24+3X=34+X
2X=10
X=5
Xiaojun = 8 + 5 = 13 years old

In the morning, Xiaojun and Xiaoqiang run along the lake with a circumference of 1800 meters. Xiaojun runs faster than Xiaoqiang. For the first time, they start from the same place and run in the opposite direction. They meet in 9 minutes. For the second time, they both slow down and run 25 meters less every minute. So, how about meeting in a few minutes? If there is a difference of 33 meters between the two men's meeting place and the meeting place just now, how many meters does the second small army run per minute?

(1) 1800 △ 9-25 × 2, = 1800 △ 200-50, = 1800 △ 150, = 12 (min); a: the two met in 12 minutes. (2) (12 × 25 + 33) △ 12-9) = 111 m. A: the second small army ran 111 m per minute

Yang Yang writes x big words every day, 104 in a week (7 days)

There are 12 students in the calligraphy group. Each of them writes 24 big characters every day. How many big characters do they write in a week (7 days)
Be sure to kiss you before 17:30.

24 × 7 = 168
168 × 12 = 2016

Yang Yang is reading a popular science book. He has read 90 pages in the first week, but there are still 13 pages left. How many pages are there in this book?

90 (1-13) = 90 (23) = 135 (pages) a: there are 135 pages in this book

Xiao Wang said: I am on a business trip for a week. The sum of the dates of the seven days plus the number of months is exactly 84. What month and date did I go on a business trip
To solve the equation of first degree with one variable

If the date of the fourth day is x and the month is y, then 7x + y = 84, because 84 is a multiple of 7 and 7x is also a multiple of 7, so y must be a multiple of 7, otherwise 7x + y = 84 does not hold, then only July in 12 months meets the condition
So the sum of dates is 7x = 84-7 = 77
x=11
So the first number before 11 is 11-3 = 8
I was on a business trip on July 8th

It took 380 meters to build a canal in four days. According to this calculation, it can be completed in another seven days. How long is the canal? (limited proportional solution)

Suppose the length of this canal is x km, from the meaning of the title: 380:4 = x: (4 + 7) & nbsp; & nbsp; & nbsp; 4x = 380 × (4 + 7) & nbsp; & nbsp; & nbsp; 4x = 380 × 11 & nbsp; & nbsp; & nbsp; & nbsp; 4x = 4180 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 1045 A: the length of this canal is 1045 km

It took 380 meters to build a canal in four days. According to this calculation, it can be completed in another seven days. How long is the canal? (limited proportional solution)

Suppose the length of this canal is x km, from the meaning of the title: 380:4 = x: (4 + 7) & nbsp; & nbsp; & nbsp; 4x = 380 × (4 + 7) & nbsp; & nbsp; & nbsp; 4x = 380 × 11 & nbsp; & nbsp; & nbsp; & nbsp; 4x = 4180 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 1045 A: the length of this canal is 1045 km