Sixth grade math problems are difficult to do, who can help me

Process a batch of parts, A first processes two-fifths of this batch of parts, and then. B processed the remaining nine deaths. It is known that the number of processed parts of B is 200 less than that of A, how many parts are there in this batch?

The total amount of B processing: (1-2 5) * (4 9) = 4 15 B is less than A: 2 5-4 15 = 2 15

This batch of parts: 200 (2 15) = 1500 pieces.

Xiaohong reads one book in three days, and reads a quarter of the whole book on the first day. I watched the remaining two-fifths in two days. The next day I read 15 more pages a day, how many pages are there in this book?

Day 2: (1-1 4) * (2 5) = 3 10 Read more the next day: 3 10-1 4=1 20 The book has a total of: 15 (1 20) = 300 pages.

A is two-thirds of B, and B is three-quarters of C. The sum of A, B, C, is 216, and how much is A, B, C

A: B = 2:3 B: C = 3:4

A: B: C = 2:3:4 (find the least common multiple to simplify) A: 2 * 24 = 48

B: 3*24=72

C: 4*24=96

1.Set x parts.

2x/5-(3/5*4/9)*x=200

x=1500

2.The book has x pages.

3/4*2/5)*x-x/4=15

x=3003.Let C be x

2 3*3 4)*x+3x 4+x=216x=96Answer: A is 48, B is 72, and C is 96

1.There are a total of 1,500 parts in this batch.

There are x parts in this batch.

2/5)x-(3/5)x*(4/9)=2002/5)x-(4/15)x=200

6/15)x-(4/15)x=200

x=200*15/2=1500

2.The book is 300 pages long.

Suppose the book has x pages, 3 4)x*(2 5)-(1 4)x=156 20)x-(5 20)x=15

x=15*20=300

3.A is 48, B is 72, and C is 96

Let C be x, then B is (3 4)x, A is (3 4)x*(2 3), x+(3 4)x+(3 4)x*(2 3)=216

x+(9/12)x+(6/12)x=21627/12)x=216

x=96, then B is equal to 96*3 4=72, and A is equal to 72*2 3=48

1.Let the velocities of A and B be x and y respectively

1/3x+1/3y=3

Solve the equation to get x=8

y=12.According to the title, -2=k+b

4=-k+b

Solve the equation to get k=

1b=-3

Because a group of 18 people, there are three groups with one less person each, then it can be seen that these three groups have 17 3 = 51 people, and because a group of 10 people has more than 5 people, so the single digit of the total number of people is 5, from which it can be seen that the single digit of the total number of 18 people is 4, and because the total number of people is between 50 and 150, it can be inferred that there are 3 groups of 18 people, so the total number of people is 18 3 + 51 = 105

There are x people, x 10 = n1 ......5，x=10*n1+5x/18=n2……15, x=18*n2+15 (a total of three people are missing, it can be regarded as a group of 15 people).

50<10*n1+5<150,50<18*n2+15<150,n1 and n2 are both integers.

N1 is between 5 and 13, and N2 is between 2 and 7. Since there are more than 5 people in a group of 10 people, the single digit of the total number of people must be 5, so only n2 = 5, that is, 18 * 5 + 15 = 105, in the case of satisfying the topic.

Xiaohua's school organizes sixth-grade students to participate in public welfare activities, and if there are more than 5 students in a group of 10 people, the number of students is 5

If a group of 18 people is in a group, there are three groups with one less person: this number is 3 less than the multiple of 18, and the multiple is 8

It is known that there are between 50 and 150 sixth-grade students: 2*18 "This number< 9*18, so it is 6*18-3=105

You can list equations: Solution: There are x people.

x/10+5=x/18-3

TO GET IT ...

Answer...

1.First ask for the purchase price of this dress 240 (1 + 20%) = 200 yuan, and then ask for huge profits, 640-200 = 440 yuan.

2 B number is 8 parts, A number is 5 parts, A is less than B (8-5) 8=, B number is more than A number (8-5) 5 = 60%.

Meters less than 24 meters: (24-18) 24 = 25%, 24 meters more than 18 meters: (24-18) 18

II. 1（×2（×）3（×）

What does it mean to make a profiteering.

1 3x x pair.

Set the purchase price to $x.

x*(1+60%)*70%-x=15

x=15÷x=125

The purchase price is 125 yuan.

10 to x is equal to 1 to 5000 and finally 50000 cm 50000 cm is equal to 500 meters 500 divided by 5 is equal to 100 The speed is 100 per minute.

The total number of trees is 112 + 13 = 125, and the survival rate of more than 80% means that it is necessary to survive 125 * 80% = 100 trees, and a maximum of 25 trees are allowed to die.

16 trees have died, that is, only 9 more trees can die, so the trees that are replaced are at least 13-9 = 4 trees.

The ratio is 42 + 28 + 30 = 100, A 42%, B 28%, C 30%.

75 times 42% =