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There are 60 people in the chorus. Boys account for two fifths of the total. How many girls are there?
36
There are 24 girls in the school chorus, and the number of girls is three fifths of the total number. How many boys are there in the chorus
The total number of singers is 24 divided by 3 / 5 = 40, so the number of boys is 40-24 = 16
How many hours is 40 minutes equal to? How many meters is 60 cm equal to? How many kg is 350 g equal to
40 minutes is the simplest fraction of 2 / 3 hours
60 cm is the simplest fraction of 3 / 5 meters
350 g is equal to 7 / 20 kg
Xinxin pinches a piece of cylindrical plasticine with a bottom radius of 2 cm and a height of 6 cm into a cone equal to the bottom of the cylinder. Do you know its height?
Please write down the formula and the result of the above question completely,
The volume of cylinder is 4 π * 6 = 24 π
After becoming a cone, the volume remains unchanged, so the cone volume = 1 / 3 * 4 π * (the height of the cone) = 24 π
The solution is that the height of the cone is 18 cm
Practical problem (formula solution)
1. There are two cups, each of which can hold 240 ml. after being prepared, we can drink one cup for each person. There are two people who use two parts of sugar and 13 parts of water to make sugar water. How many ml of sugar and water do you need?
2. According to the work performance, the bonus of 4830 yuan will be awarded to three people (a, B and C) according to 6:7:8?
Sugar 240 * 2 / 15 = 32 (ML)
Water 240 * 13 / 15 = 208 (ML)
Because there are two people, the sugar needs 32 * 2 = 64 ml, and the water needs 208 * 2 = 416 ml
2) A 4830 * 6 / 21 = 1380 yuan
B 4830 * 7 / 21 = 1610 yuan
C 4830 * 8 / 21 = 1840 (yuan)
Volume conversion, cubic millimeter, cubic centimeter, cubic decimeter, cubic meter, cubic kilometer, for example, how many cubic centimeters is one cubic millimeter, thank you~
Cubic millimeter, cubic centimeter, cubic decimeter, cubic meter, the rate of advance between every two adjacent units is 1000
Large units for small units multiplied by the rate of 1000. Small units for large units divided by the rate of 1000
Cubic meters, cubic kilometers of the rate is 1000000000
1 cubic millimeter = 0.001 cubic centimeter
1 cubic millimeter = 0.000001 cubic decimeter
20 practical problems and answers of solving elementary equations (equation of one variable and one degree)
Set the wall area to be painted in each room as X
According to the meaning of the question: (8x-50) / 3-10 = (10x + 40) / 5
Solve the equation: x = 52
How to calculate 624 times 78
624*78
=(600+24)*(100-22)
=60000+2400-13200-528
=62400-13728
=48672 .
Redundancies
Radical (15 + 161)
In order to simplify this kind of radical, the first radical must be changed into the form of (a + b) ^ 2
(a+b)^2=a^2+2ab+b^2
Let a ^ 2 + B ^ 2 = 15 2Ab = root 161
4 (AB) ^ 2 = 161 B ^ 2 = 15-a ^ 2
4a^2(15-a^2)=161
4a^4-60a^2+161=0
a1^2=7/2 a2^2=23/2
b1^2=23/2 b2^2=7/2
It's actually a set of numbers
15 = (root (7 / 2)) ^ 2 + (root (23 / 2)) ^ 2
Root 161=
Original formula = root ((root (7 / 2)) ^ 2 + 2 × root (7 / 2) × root (23 / 2) + (root (23 / 2)) ^ 2)
=Root ((root (7 / 2) + root (23 / 2)) ^ 2)
=± (root (7 / 2) + root (23 / 2))
=± (radical 14 + radical 46) / 2
Answers to the first semester mathematics midterm paper of grade seven
Examination time: 90 minutes proposition: grade two lesson preparation group review: Zhang Tong proofread: Fei Guohua, Hu Chunlei
Reference answer
1、 1, 2, 3, 7, 4, 5
6. 8 7, equal and equally divided 8, 2 9, isosceles right angle 10
2、 11, C 12, a 13, C 14, C 15, a
16、B 17、A 18、D 19、B 20、D
3、 21, 1 0, 2 180, 4
22、① ②
23. It is proved that the root is increased and the original equation has no solution
24. Proof: Yes, it is the midpoint,
It's a rectangle
When, when, when, denominator
When, when, when
The square root of is
27. Original form
.
If the bicycle speed is km / h, the car speed is km / h
29. ①. Prove that it is an equilateral triangle
② When it is a midpoint, it satisfies the meaning of the question. It is a midpoint and an equilateral triangle. Bisection is an equilateral triangle,
, ,
For
RELATED INFORMATIONS
- 1. The number of female students in a class is one fifth more than that of male students. The number of male students is () of that of female students. The number of female students is () of that of the whole class
- 2. There are 2 more girls and 22 more boys in a class than 3 / 5 of the class. How many students are there in the class?
- 3. There are 20 boys and 5 / 9 girls in a class. How many students are there in the class A few more Pile a coal is 4 / 5 of pile B coal. If 8 tons are transported from pile B to pile a, pile B is 40 tons more than pile A. how many tons are there in pile a and pile B? How many cuboids do you need to build a cube with a cuboid 12 cm long, 8 cm wide and 10 cm high? Xiao Ming planted a tree every 6 meters along the same road, with a total of 31 lessons. Now Xiao Ming wants to plant a tree every 8 meters without his brother. How many trees should there be without moving? 1 extra point for answering within 1 hour!
- 4. The number of boys accounts for 60% of the class. How many% more boys than girls? How many% less girls than boys?
- 5. If the ratio of girls in a class to the whole class is 7:10, how many percent more girls than boys? Formula
- 6. When x equals 2, what is 3x
- 7. -What is x + 5 = 2 / 3x?
- 8. What is 2x × (3x-5) × x equal to
- 9. What process is 3 / 8 (3 / 8-1 / 4)
- 10. One ninth of a five meter meter is equal to a fraction of a meter, and a fraction of an hour is equal to a third of two hours
- 11. There are 44 students in class 5 (2), including 24 boys and 20 girls. Boys account for ()% of the class
- 12. There are 44 students in Grade 5 (3) class of sunshine primary school, among which boys account for 5 / 11 of the total number of students in the class, and the number of girls in class 5 (2) is 7 more than that of girls in class 5 (3) So how many girls are there in no (2) class?
- 13. The number of girls in class 52 accounts for three fifths of the class. What percentage of boys in girls? What percentage of boys in girls
- 14. The number of boys in a class is 6 more than 5 / 7 of the whole class, and the number of girls is 4 less than 1 / 4 of the whole class
- 15. Boys account for 5 / 9 of the total number in class 52. After 4 girls are transferred, boys now account for 3 / 5 of the total number
- 16. The ratio of boys to girls is four fifths, and boys account for four ninths of the total
- 17. The number of boys in a three-year class is 4 less than 5 / 9 of the whole class. The number of girls in a three-year class is 6 more than 2 / 5 There are six more girls than two fifths of the class
- 18. The number of boys in class 6 (2) is 5 less than 60% of the class, and the number of girls accounts for half of the class. How many girls are there in this class? emergency
- 19. In class 62, the ratio of boys to girls is 9:7. There are six more boys than girls. How many students are there in class 62
- 20. In class 6 (1), boys account for 5 / 9 of the class and girls account for 1 / 2 of the class Is it right or wrong?