Xiaoming and Xiaogang have more than 100 books. If Xiaoming gives Xiaogang x books, Xiaoming's books are 3 / 7 less than Xiaogang's; if Xiaogang gives Xiaogang x books, it is smaller Just give Xiaoming x books, Xiaogang's books are 3 / 8 less than Xiaoming's. In order to find x, we must calculate the formula, not the quadratic equation of two variables, but try to calculate it

According to the title, when Xiaoming gave Xiaogang x copies, the ratio of Xiaoming to Xiaogang was (1-3 / 7): 1 = 4:7. According to the title, when Xiaogang gave Xiaogang x copies, the ratio of Xiaoming to Xiaogang was 1: (1-3 / 8) = 8:5. According to the title, this batch of books is not only a multiple of 7 + (7-3) = 11 (but also a multiple of 8 + (8-3) = 13)

Xiao Ming and Xiao Gang have more than 100 books. If Xiao Ming gives Xiao Gang x books, then Xiao Ming's books are 3 / 7 less than Xiao Gang's; if Xiao Gang gives Xiaogang x books Xiaogang's books are 3 / 8 less than Xiaoming's. What is x

If Xiaoming gives Xiaogang x books, the ratio of Xiaoming to Xiaogang's books is (1-3 / 7): 1 = 4:7
If Xiaogang gives Xiaoming x books, the ratio of Xiaoming to Xiaogang's books is 1: (1-3 / 8) = 8:5
Since the total number of books is constant, it should be the least common multiple of (4 + 7) and (8 + 5), that is, 11 × 13 = 143 copies
If Xiao Ming has a book, x = 4 × 143
If Xiao Gang gives Xiao Ming x books, Xiao Ming has 143 × 8 / (8 + 5) = 143 × 8 / 13 = 88
52+x=88-x
2x=88-52
2x=36
x=18
A: X is 18

Xiao Gang met his new friend Xiao Ming in the library. He wanted to know his age He said you put your age - 5 and then * 2 - half of the result and then + 11 asked Xiaoming's age

Xiao Gang's age has not been said. If we use the algebraic formula, it is:
(x-5)*2/2+11=(x-5)+11=x+6

Xiaoming and Xiaogang each take a book. The page number of Xiaoming's book is 183 words. Xiaogang's book is 5 pages more than Xiaoming's

1-9 is a word on a page. There are 9
10-99 is a page of two words.. a total of 200.. plus the previous -- - 200 + 9 = 209
So it's less than 99 pages
209-183=26 26*2=13..
So the book is 13 to 99 pages short
86 + 5 = 91.. 91 pages in total, 193 words

Xiao Ming went to the store and bought 10 exercise books and 6 pencils, which cost 7 yuan and 1 jiao. He knew that one exercise book pen costs 1.5 cents How much are the exercise books and pencils?

Six pencils are less than six exercise books
15 × 6 = 0.9 yuan
10 + 6 = 16 (exercise books)
7.1 + 0.9 = 8 yuan
Each exercise book
8 △ 16 = 0.5 (yuan)
Each pencil
5-0.15 = 0.35 yuan

Xiao Ming took 15 yuan to the store to buy Stationery, 2 / 3 for pencil box, 1 / 4 for book and the rest for pen Q: how much did Xiao Ming spend on pencil case, notebook and pen?

It costs 10 yuan to buy a pencil box, and 2.5 yuan for a book and a pen

Xiao Ming bought three pencils and three exercise books. The salesman asked him to pay 3 yuan and 50 yuan. Xiao Ming said that the salesman must have miscalculated the account. Can you tell me why Xiao Ming bought three pencils and three exercise books. The salesman asked him to pay 3 yuan and 50 yuan. Xiao Ming said that the salesman must have miscalculated the account. Can you tell me why? Hurry up

Pen x Ben y
3(x+y)=3.5
3.5 is not divisible by 3, so it's wrong

Xiao Ming bought x pencils, which cost y yuan. The second time, the price of pencils was 20%. He bought 10 pencils more than the last time. He spent 4 yuan on them. He asked Xiao Ming to buy a total of pencils twice?

If this is just a simple equation problem, then before solving this problem, first make sure that X and y are integers
When y is an integer, the answer is: x = 15, y = 3 and x = 40, y = 4
Now let's talk about the problem-solving process:
Suppose the unit price of pencil is a; then two equations can be listed according to the title, namely:
x*a=y ----(1)
（x+10）*(1-20%)*a=4---(2)
By comparing the left and right correspondence of the above two equations and eliminating a, we can obtain that:
The further evolution of X / 0.8 (x + 10) = Y / 4 can be obtained
X / x + 10 = Y / 5, and then the equation is expressed as the value of X expressed by Y, that is:
x=10y/(5-y)
Since the denominator is 5-y and must be greater than 0, the values of Y are determined to be 1, 2, 3 and 4
Then we can get two kinds of answers by taking the four values of Y into consideration
x=15,y=3
x=40,y=4
Wow, I'm so tired!
It's over, landlord
In addition, y is not specified as an integer, it is difficult to solve, you can try to use the program to achieve ~!

Li Hua rode a racing car from home to Leshan Xincun square. When he went there, he traveled 24 kilometers an hour and came back 16 kilometers an hour. The average speed of a round trip was () km / h A. 20 B. 19.8 C. 19.6 D. 19.2

（1+1）÷（1÷24+1÷16），
=2÷（1
24+1
16），
=2÷5
48，
=2×48
5，
=19.2 (km),
A: the average speed of a round trip is 19.2 kilometers per hour
Therefore, D

Xiaohua spends 8.8 yuan on pencils and notebooks, and 2.4 yuan less on pencils than notebooks. How much does it cost to buy pencils and notebooks?

Suppose X Yuan for pencil and X + 2.4 yuan for notebook
x＋x＋2.4＝8.8
x＝3.2