Xiao Li read a book. On the first day, she read 13 pages more than 2 pages of the whole book. On the second day, she read half of the whole book less than 1 page. There are 23 pages left to read. How many pages are there in the whole book?

Xiao Li read a book. On the first day, she read 13 pages more than 2 pages of the whole book. On the second day, she read half of the whole book less than 1 page. There are 23 pages left to read. How many pages are there in the whole book?

Suppose the total number of pages in this book is x, then (13X + 2) + (12x-1) = x-23, and the solution is x = 144
Solving a math problem
59x + 53Y = 590745, how much is x and y? It requires XY to be integers, thank you
59*9974+53*43=590745
59*（9974-53）+53*（43+59）=590745
59*（9974-53*2）+53*（43+59*2）=590745
59*（9974-53*3）+53*（43+59*3）=590745
…………
It's all about calculation
If there is a set of integer solutions, then there is no array integer solution.
。。。。 There are innumerable solutions to the equation of degree 2.. However, there is an integer limit, =. =There should be a lot of them too!!!
Put the nine numbers 1 ~ 9 into the box to make the equation hold
（6）÷（2）=（9）÷（3）=（1）（7）（4）÷（5）（8）=3
Locate 12369 first
（6）÷（2）=（9）÷（3）=（1）（）（）÷（）（）=3
Locate the 48
（6）÷（2）=（9）÷（3）=（1）（）（4）÷（）（8）=3
Finally, the position of 57 is determined and the result is obtained
（6）÷（2）=（9）÷（3）=（1）（7）（4）÷（5）（8）=3
（9）÷（3）=（6）÷（2）=（1）（7）（4）÷（5）（8）=3
（9）÷（3）=（6）÷（2）=（1）（7）（4）÷（5）（8）=3
A: from the meaning of the question:
1. Among the nine numbers of 1 ~ 9, there are three cases that can form the equation of () / () = 3, namely, 3 / 1 = 3, 6 / 2 = 3 and 9 / 3 = 3. And the number can not be repeated, so it can only be a combination of 3 △ 1 = 3, 6 △ 2 = 3 or 9 △ 3 = 3, 6 △ 2 = 3. So 6 and 2 must appear in the first two equations.
2. Analysis of the third equation, a three digit divided by a two digit equal to 3, we can be regarded as a three digit divided by 3 and so on
It's in two digits. Then we can get the conclusion that
A: from the meaning of the question:
1. Among the nine numbers of 1 ~ 9, there are three cases that can form the equation of () / () = 3, namely, 3 / 1 = 3, 6 / 2 = 3 and 9 / 3 = 3. And the number can not be repeated, so it can only be a combination of 3 △ 1 = 3, 6 △ 2 = 3 or 9 △ 3 = 3, 6 △ 2 = 3. So 6 and 2 must appear in the first two equations.
2. Analysis of the third equation, a three digit divided by a two digit equal to 3, we can be regarded as a three digit divided by 3 and so on
In a two digit number. Then it can be concluded that the hundred of this three digit number is either 1 or 2. Because 2 will appear in the previous equation, the hundred of this three digit number can only be 1. Because divide by 3 to get an integer, the characteristic of the number is that the number of each digit can be divided by 3. The number can't be repeated. It can be inferred that the three digits may be the following numbers: 138, 174, 183 and 189.
3. Divide the above four good three digits by three to get the following numbers: 46, 58, 61, 63. Because 6 and 2 will appear in the first two equations, the third equation is determined as 174 △ 58 = 3.
4. Finally, the first two equations are 9 △ 3 = 3 and 6 △ 2 = 3. Put it away
There are 100 pages in a story book. On the first day, Xiao Hong read a quarter of the whole book. On the second day, she read 20 pages. What percentage of the whole book did she read in two days?
Total = 1 / 4 + 20 △ 100 = 9 / 20
An electrical mathematics problem
Please specify the algorithm
Two lamps are connected in parallel, and the current flowing through them is 750 ma. The ratio of the resistance of the two lamps is 1: what is the current flowing through the resistance R (the first lamp)
According to the current formula: I = u / R, the current flowing through all electrical appliances in the parallel circuit is inversely proportional to the resistance. If the ratio of resistance 1 to resistance 2 is 1:2, the current ratio is 2:1. According to the total current of 750ma, the current flowing through the first lamp is I1 = 750 × 2 / / 3 = 500 (MA)
This middle school textbook has its own look
The ratio of the current flowing through the two resistors is 2:1, and the parallel voltage is equal, so the current is the inverse ratio of the resistance.
In parallel, the ratio of current is the inverse ratio of resistance, that is, I1: I2 = R2: R1
So I1 = I * R2 / (R1 + R2) = 750 * 2 / 3 = 500mA
What is the title?
An electrician question is still in junior high school, but it seems that there is a direct formula in the electrical technology foundation. I do not deduce it. I1= (R2/R1+R2) *I, I2= (R1/R1+R2) *I, I have no word to write, only 100 words, R1/R2=1/2 get R2=2R1, this is not for me, it is too suck, my formula is direct. finish
Put the nine numbers 1-9 in the box below to make the equation true
( )*( )-( )=( )( )/( )( )+( )=( )
Fill in a number in brackets. The middle part is the quotient of two digits divided by two digits plus one digit
2*5-7=96/48+1=3
A book has 300 pages. Xiao Li read 1 / 6 of the whole book on the first day and 2 / 15 of the whole book on the second day. What page should she read on the third day?
If this is a math problem, the answer is as follows: 300 times 1 / 6 = 50 (page) 300 times 2 / 15 = 40 (page) 50 + 40 + 1 = 91 (page) answer: the third day should start from page 91. If this is a sharp brain turn, the answer may be: no answer, the first day saw 300 * 1 / 6 = 50, the second day saw 300 * 2 / 15 = 40, the second day did not know
On the first day, I read 1 / 6 * 300 pages = 50 pages
The next day I read 2 / 15 * 300 pages = 40 pages
So the third day should start from page 50 + 40 + 1
From page 91
On the first day, 1 / 6 of the book is 50 pages. On the second day, 2 / 15 of the book is 90 pages. On the third day, we should start from 91 pages.
1 / 6 * 300 pages = 50 pages
2 / 15 * 300 pages = 40 pages
From page 91
1 / 6 * 300 pages = 50 pages
2 / 15 * 300 pages = 40 pages
The formula calculation should be as follows:
300*（1/6+2/15）+1
=300*1/6+300*2/15+1
=50+40+1
=91 (page)
A: the third day should start from page 91
There is no answer. The first day I saw 300 * 1 / 6 = 50, and the second day I saw 300 * 2 / 15 = 40. I don't know which page I started to read the next day. I may repeat it and review it
300*1/6=50
300*2/15=40
50+40=90
A: the third day should start from page 91
The first day I saw 300 * 1 / 6 = 50, the second day I saw 300 * 2 / 15 = 40, so the third day I started from page 91
She likes to look from the page
What grade is this? It's so simple! It's 91 pages!
Ninety-one
Ninety-one
Another way to solve the problem:
Divide 1 / 6 and 2 / 15 to get 3 / 10
300*3/10=90
This is the end of reading, to continue to read, we have to turn the previous page, so the conclusion is 91
Now I take the daily turnover in the coffee shop. Recently, the business is not very good, and the turnover is not very much. When I get paid, the boss doesn't give it to me. He says that the turnover is with you, so I use the turnover first, but I don't know how much I spend now. All the business, minus all the purchasing expenses, the money handed over to the boss is not enough, I don't know how to calculate. My salary is 2500
All sales should be recorded, small ticket stub
If you add up the sales records such as the stub, minus the remaining turnover, it will be the money you spent
All business, minus all purchase expenses, this is only the profit. You can only give the boss the profit, because turnover also includes purchase cost
Fill in the box with nine numbers from 1 to 9 to make the equation true
Put the nine numbers 1-9 in the air to make the three equations hold (can't be repeated)
①（ ）+（ ）=（ ）
②（ ）-（ ）=（ ）
③（ ）*（ ）=（ ）
Put the nine numbers 1-9 in the air to make the three equations hold (can't be repeated)
①（ 4）+（ 5 ）=（ 9 ）
②（8 ）-（ 7）=（ 1）
③（2 ）*（ 3）=（ 6）
Hope to adopt
1+7=8
9-4=5
2*3=6
2*3=6，4+5=9,8-7=1.
1+7=8
9-5=4
2*3=6
There are 270 pages in a book. Xiao Li read 415 of the book on the first day and the remaining 49 on the second day. How many pages has she read?
270 × 415 + (270-270 × 415) × 49, = 270 × 415 + (270-72) × 49, = 72 + 198 × 49, = 72 + 88, = 160 (page), a: she has read 160 pages