Brave challenge make a question and write, column plus a reward! 5

1.Solution: Suppose that the total book is x.

Reference Book: 180

Science Book: x 3

Literature and Art Book: (180+x 3) 5

Then: x=180+x 3+(180+x 3) 5,x=3602Solution: There are x boys and 156-x girls.

10x/11=2(156-x-12)

x = 88, i.e. 88 boys and 68 girls.

3.Solution: Set up x books of literature and technology, and the number of books after the change is 1880-2x 5-50+40, which is three times the number of any kind of books at this time, that is, 9x 5

1880-2x/5-50+40=9x/5

x = 850 copies.

3x/5=y-50

y=460 copies.

for 570 copies.

Set up x books of literature and art, and y of science and technology, the number of books after the change is 1880-2x 5-50+40, which is three times the number of any kind of books at this time, that is, 9x 5

1880-2x/5-50+40=9x/5

x = 850 copies.

3x/5=y-50

y=460 copies.

for 570 copies.

A total of 360 copies.

10 11 divided by 2 = 5 11

156-12) (1+5 11)=99 (person) 156-99=57 (person).

There are 99 boys and 57 girls.

1870 divided by 5 11 = 850 (literary book).

850 multiplied by 3 5 + 50 = 560 (science book).

850 times 3 5-40 = 470 (***).

This kind of fraction problem first finds the unit 1, finds the fraction corresponding to the specific quantity, and draws a line segment diagram to help understand.

1. If the total number is x, then the literature and art books are 2x 3-180, which is also (180+x 3) 5

That is, 2x 3-180 = (180 + x 3) 5x = 360 copies.

2. There are x male students and 156-x female students.

10x/11=2(156-x-12)

x = 88, i.e. 88 boys and 68 girls.

3. Set up x books of literature and art, and Y of science and technology books, and the number of books after the change is 1880-2x 5-50+40, which is three times the number of any kind of books at this time, that is, 9x 5

1880-2x/5-50+40=9x/5

x = 850 copies.

3x/5=y-50

y=460 copies.

for 570 copies.

One. Set: The total book is x.

Reference Book: 180

Science Book: x 3

Literature and Art Book: (180+x 3) 5

Then: x=180+x 3+(180+x 3) 55x=6(180+x 3).

3x=6*180

x = 360 two. Man; x

F: 156-x

x10/11=2*（（156-x）-12）10x=22*（144-x）

32x=22*144

8x=11*72

x=99 male; 99

Female: 156-99=57

Three: Literary books: x

Original ***: 3x 5-40

Tech Book: 3x 5+50

1880=x+3x/5-40+3x/5+501870=x+6x/5

1870*5=11x

x=170*5=850

2 Male: 99 Female: 57

3. Literature and art books: 850

Science & Technology Book: 560

***：470

It's too hard, right, I just went to college.

52 4 51 6 514 (m).

514 536 1050 (m).

1050 105 10 (min).

A: It takes 10 minutes.

The total length of the team is 52 * 4 + 51 * 6 = 514 meters.

Total distance = 536 + 514 = 1050 meters.

1050 105 10 (min).

If this equation is 0, then the denominator cannot be zero, and the numerator is zero.

So (x-8)(x+1)=0

So x=8 or x=-1

Again|x|-1 cannot be zero, so x cannot be 1 or -1 so x=8

[(x-8)(x+1)] / (|x|-1) is 0

then (x-8)(x+1)=0 and |x|Not equal to 1

So x=8

[(x-8)(x+1)] / (|x|-1)=0[(x-8)(x+1)] =0 (1)

and (|x|-1<>0 (2)

From (1), we get x=8 or x=-1

From (1), we get x<>1 and x<>-1

So x=8

The denominator cannot be 0!So it can only be (x-8)(x+1)=0 and you get x=8 and x=-1 but according to the denominator! x=-1! It will be 0 so! x can only be 8

Ton. 12 (8-6) = 6 tons.

6 8 = 48 tons.

Answer: The original plan was to transport 48 tons in 8 hours.

Ton. Ton. Sky. 16 tons.

Answer: This batch of coal in the town is a total of tons of coarse grades.

Xie Lianghuai: 1) More than 6 hours to transport tons.

The original plan was 9-3 = 6 tons.

6 8 = tons per Jing Lun Friend Xiao Tong Crack Hourly Transport. Answer...

I actually burn it every day.

Ton. Burning 2 days longer than originally planned, it saved the same amount of time than originally planned.

Ton. It was originally planned to burn. Sky.

These coals are altogether.

Ton. I don't understand, please ask, I wish you a happy o(o

1. The output value of a fertilizer factory this year has increased by 20% compared with last year, an increase of 5 million yuan over last year, how much is the output value of this year?

500 20% = 2500 (tons) 2500 (1 20%) = 3000 (10,000 yuan).

A: This year's output value is 30 million yuan.

2. The fruit company stores a batch of apples, and after selling this batch of apples for 30, it ships 160 boxes, which is 1 10 more than the original stored apples, how many boxes of apples are there at this time?

160 (30% 1 10) = 400 (boxes) Answer: There are 400 boxes of apples at this time.

3. The original price of a commodity is 20% less than the current price, and the current price is 1028 yuan, how much is the original price?

（1/50-1)*(1/49-1)*(1/48-1)*.1/4-1)*(1/3-1)*(1/2-1)

1 50 (49 negative numbers are multiplied, so it is negative).

The numerator of the previous fraction is the same as the denominator of the latter number, so it can be reduced).

1. The area formula of the trapezoid is s=1 2 * height * (upper bottom + lower bottom), and the area is the largest when the height is taken as the maximum.

The area is 1 2 * = square meters.

2. A and B each take a round, up to 3 + 1 = 4, 130 4 = 32, the remaining 2 Therefore, A takes 2 first, and then no matter how many roots B takes, A guarantees that the number of matches and B add up to 4, which can ensure that A takes the last match.

With A and B as the base, C is the highest area.

Trapezoidal area = (upper bottom + lower bottom) height 2

Take a, b as the base, c as the high: s=(

Take a, c as the base, b as the high: s=(

Take b,c as the base, and a as the high:s=(

Therefore, with a and b as the base, c is the height and the area is the largest.

If B takes first and A takes later, then the sum of the quantity taken by A and the quantity taken by B must be a multiple of 3 (e.g., B takes 1 root, A takes 2 roots; B takes 3 roots, A takes 3 roots) will win!

If A takes first, B takes later, A takes 3 at the beginning, and then the same as above, the number of A and the number of B must be added to be a multiple of 3, and you will win!

With c as the height, a and b as the upper and lower bottoms, the trapezoidal area is the largest, and the area formula s=(upper bottom + lower bottom) is 2.

130 3 = 43 is more than 1, so if each person draws three sticks each time, they can draw 44 times, as long as A draws first, three sticks will win each time.

I don't know what a good way to do the first question, and the direct calculation is that c is high ab, and the second question is the bottom and bottom, respectively: the total number (the maximum number of numbers, the minimum number of numbers) The number of times you take ......If the number is zero, the winner wins.

In other words, take 2 first, and then every 2 times, a total of 4.

1. A and B do the upper and lower bottoms, C do the high, do right-angle trapezoids, and the area is maximum according to the height * (upper bottom + lower bottom) 2, considering the nature of the inequality, it can be known that when the value of the height and (upper bottom + lower bottom) is closer to the product, the larger the product, so choose a and b to do the upper and lower bottoms, C to do high, do right-angle trapezoids, the area is the largest, and the drawing can also be seen, at this time, the figure is closest to the rectangle.

2. Scheme: A draws 2 first, and after each time B draws it, A will draw the first root accordingly, and you can win.