Math problems, who will help me solve them, and who can help me solve math problems?

Analysis: In this question, the percentage of trees planted in class A, B, and C is known, and only the sum of trees planted is required. Because when class A plants 200 trees, it is exactly 2 7 of the sum of the three classes of tree planting, so the total number of trees planted = 200 2 7 = 700 (trees), because overtime needs to plant 40% of the total trees of the three classes, so class A needs to plant 700 40% = 280 (trees).

Then class B and class C planted a total of 700-280 = 420 (trees). And because the ratio of trees planted in class B and C is 4:3, the tree planting in class C is 420 3 (4+3)=180 (trees).

Solution: The total number of trees planted is: 200 2 7 = 700 (trees) Class A to plant trees: 700 40% = 280 (trees).

Trees planted in Class B and Class C: 700-280 = 420 (trees) Tree planting in Class C: 420 3 (4+3) = 180 (trees) Answer: 180 trees were planted in Class C.

Reflection: Step-by-step solutions can solve such problems.

I hope it helps, and I wish you progress in your grades.

The total number of trees planted is 200 2 7 = 200x7 2 = 700.

The number of trees planted is 700x(1-40%)=700x60%=420.

Therefore, the planting of trees in class C is 420x3 (4+3)=420x3 7=180 trees.

If a tree is planted in class C, it will be 4 3a in class B and B in class A

40%(a+4/3a+b)=b b=14/9a

2/7(a+4/3a+b)=200 a=180

(1) Oriental Pearl TV Tower = 405 x (1 + 7 45) = 468 meters (2) Number of more boxes = 120 x 1 4 = 30 cartons of milk shipped 120 + 30 = 150 cartons.

3) 48 x 1 2 x (1-1 3) x (1-1 4) x ...x (1-1/8)

48 x 1/2 x 2/3 x 3/4 x...x7/8= 48 x 1/8

6 yuan. Answer.

(1) ** TV Tower is 405 meters high, and the Oriental Pearl TV Tower is 7/45 higher than ** TV Tower. How tall is the Oriental Pearl TV Tower?

468 meters. The Oriental Pearl TV Tower is 468 meters high.

2) A supermarket shipped 120 cartons of juice, and the milk was a quarter more than juice. How many cartons of milk are shipped than juice? How many cartons of milk have been shipped?

30 cartons more milk than juice were delivered. 150 cartons of milk arrived.

3) On Monday, her mother gave Xiaofang 48 yuan of pocket money for a week, and she used half of the total number to buy school supplies that day, the remaining third on Tuesday, and the remaining quarter ,...... on WednesdayAt the end of 1 week, there is some money left in the tower, how much?

After the end of 6 yuan 1 week, she still has some money left, which is 6 yuan.

(1) 405 + 405 * 7 45 = 405 + 63 = 468 (2) 120 * 1 4 = 30 120 + 30 = 150 (3) buy school supplies courage 48 * 1 2 = 24 yuan.

There are 48-24=24 yuan left.

Tuesday uses 24 * 1 3 = 8 yuan.

There is still 24-8 = 16 yuan.

Wednesday uses 16 * 1 4 = 4 yuan.

There is still 16-4 = 12 yuan.

Thursday 12*1 5=RMB.

There are still dollars left. Friday dollars.

There are still dollars left. Saturday 8 * 1 7 = 8 7 yuan.

There are 8-8 7 = 48 7 yuan left.

Day t of the week 48 7 * 1 8 = 6 7 yuan.

There are 48 7-6 7 = 6 yuan left.

6 divided by 2 equals 3, multiplied by 1+2 is 3 times 3 = 9

Among those who tested positive, those who did have cancer were: 4% * 95%, and those who did not have cancer were: (1-4%)*1-96%) = 96% * 4%.

Therefore, the probability that a person who has a positive test result does have cancer is:

People who do have cancer: 4% * 95%, people who do not have cancer are: (1-4%)*1-96%) = 96% * 4%.

Therefore, the probability that a person who has a positive test result does have cancer is:

Probability that a positive person does have cancer = 4% * 95% =

（95%*4%）/ [ 95%*4%+(1-4%)*1-96%)]= 。。Probability and Statistics Typical Questions.

The circumference of the circle is c=2 r=2*

So ab length =

Because the fan is conical on the side.

So the circumference of the bottom surface of the cone =

So the radius of the bottom surface of the cone =

So the base area s= r =

Find the volume of the rotating body formed by the rotation of the graph around the x-axis of the line segment [0, 2] on the x-axis by the functions y=sinx, y=cosx, x-axis?

Solution: v=[0, 4) sin xdx+[ 4, 2] cos xdx

0，π/4](π2)∫(1-cos2x)dx+[π4，π/2](π2)∫(1+cosx)dx

0，π/4][(2)∫dx-(π4)∫(cos2xd(2x)]+4，π/2][(2)∫dx+(π4)∫cos2xd(2x)]

(2)x-(π4)sin2x]︱[0，π/4]+[2)x+(π4)sin2x]︱[4，π/2]

Solution: Set up a table for x yuan each.

Then the column equation is:

32*4+2x=138

128+2x=138

2x=10x=5A: 5 yuan per table.

1.On Teacher's Day, the students made paper flowers, the fifth grade made M flowers, and the sixth grade was twice that of the fifth grade. In the sixth grade, I made paper flowers, and I made a total of ( ) flowers in the two grades, and I made more ( ) flowers in the sixth grade than in the fifth grade.

2.The price of a fountain pen in the store is 5 yuan more than 2 times that of a ballpoint pen, if the price of a ballpoint pen is x yuan, then the fountain pen will cost (2x+5) yuan, and when x = 15, the fountain pen will cost 35 yuan.

3.Mr. Lin bought 15 fountain pens and rewarded the students, each of which was $x, and paid 50 yuan to get back (50-15x) yuan.

4.According to the equivalence relationship in the problem, complete the equation.

Road repair is to build a road 800,000 acres long, x kilometers per day, 8 days of repair, there are still 80 kilometers left.

800-8x ）=80

8x+80 ）=800

5 (65) is 2 times less than 35 times less than 5; 35 times less than (20) 2 times less than 5

Elementary? Please, I'm a senior in high school.

1.The first parenthesis (, the second (the third)

2.（2x+5）

3.（50-15x）

4.The first (800-80x) The second (8x+80)5The first (65) The second (20).