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30 tháng 3 2023

Tổng của dãy số trên bằng 2041210

30 tháng 3 2023

tổng là 2043231

6 giờ trước (20:45)

ψ(`∇´)ψ Like cái kìa !!!!

Đặt số ban đầu có hai chữ số là AB, với A và B lần lượt là chữ số hàng đơn vị và hàng đơn vị.

Theo yêu cầu của bài toán, số mới khi thêm chữ số 7 vào bên phải sẽ là AB7.

Ta có phương trình:
AB7 - AB = 565

Đổi số AB7 thành dạng toán học: 100A + 10B + 7

Kết hợp với phương trình ta có:
100A + 10B + 7 - (10A + B) = 565
100A + 10B + 7 - 10A - B = 565
90A + 9B + 7 = 565
90A + 9B = 558
10A + B = 62

Vì A và B đều là số tự nhiên từ 0 đến 9, ta thử các giá trị có thể của A và B:
- Thử A = 6, B = 2: 62 không lớn hơn 565 đơn vị, loại.
- Thử A = 5, B = 7: 57 không lớn hơn 565 đơn vị, loại.
- Thử A = 4, B = 7: 47 không lớn hơn 565 đơn vị, loại.
- Thử A = 3, B = 2: 32 không lớn hơn 565 đơn vị, loại.
- Thử A = 2, B = 7: 27 không lớn hơn 565 đơn vị, loại.
- Thử A = 1, B = 2: 12 không lớn hơn 565 đơn vị, loại.

Vậy giá trị của A và B là 7 và 1. Vậy số cần tìm là 71.

6 giờ trước (20:57)

ko biet

 

6 giờ trước (20:35)

Chọn D

Số lượng phần tử: \(\dfrac{\left(2023-1\right)}{2}+1=1012\)

Số cặp là: \(\dfrac{1012}{2}\)

Kết quả biểu thức: \(\dfrac{1012}{2}\cdot2=1012\)

Chọn D

A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 34 to 40 Some Russian women became well-known fighter pilots during the Second World War. Yekaterina Budanova was one of them. She joined the Soviet Army and became a lighter pilot after working as a non-military pilot. At first, Budanova's officer didn't believe in her ability. But in a short time Budanova became famous for her talent and remarkable flying skills. Unfortunately, she died at the...
Đọc tiếp

A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 34 to 40

Some Russian women became well-known fighter pilots during the Second World War. Yekaterina Budanova was one of them. She joined the Soviet Army and became a lighter pilot after working as a non-military pilot. At first, Budanova's officer didn't believe in her ability. But in a short time Budanova became famous for her talent and remarkable flying skills. Unfortunately, she died at the age of 26 in air-to-air fighting against German planes although she already shot down one plane and hit a second before being shot down herself.

 Interested in flying at an early age, Lydia Ultvyak joined a flying club and performed her first solo flight at the age of 15. She became a fight instructor after graduating from the military flying school. After the German attack on the Soviet Union in 1941. Utvyak joined the Soviet Air Force and soon achieved great success. Like Budanova, she was killed (at the age of 21) in fighting against German planes. And along with Yekaterina Budanova Lydia Utvyak is often considered one of the world's most famous female fighter pilots.

 

Question 34. Which of the following best serves as the title of the text?

       A. Russian Female Fighter Pilots                             B. Female Fighter Pilots Who Made History

       C. Women during the Second World War               D. Fighting the Germans

 Question 35. The fact that Litvyak had her first solo flight when she was only 15 implies that __________.

       A. it was a risky thing to do                                     B. she loved danger

       C. she had a natural talent for flying                        D. her flying club was the best in the world

 Question 36. What did Budanova do before she become a fighter pilot?

       A. She worked at a flying club.                                B. She was a Russian officer.

       C. She worked as a non-military pilot.                    D. She shot down German planes.

 Question 37. The word 'solo' in paragraph 2 is opposite meaning to ________.

       A. done by one person alone                                    B. successful                                             

       C. done by more than one person                             D. single

 Question 38. The phrase "a second" in paragraph 1 refers to _______.

       A. the Second World War                                                                                B. a second German plane          

       C. a second Russian plane                                       D. a fighter pilot

 Question 39. The word "them" in paragraph 1 refers to_______.

       A. fighter pilots                                                        B. well-known fighter pilots

       C. some Russian women                                          D. women    

 Question 40. Which of the following is NOT true about Budanova and Uitvyak, according to the text?

       A. They died in their twenties.

       B. They died when the Second World War was over.

       C. They were talented and successful female fighter pilots in the Soviet Air Force.

       D. They are considered two of the world's most famous female fighter pilots.

2
PQ
Phan Quỳnh
Giáo viên
6 giờ trước (20:33)

34. B

35. C

36. C

37. A

38. C

39. C

40. B

3 giờ trước (23:47)

Question 34. Which of the following best serves as the title of the text?

       A. Russian Female Fighter Pilots                             B. Female Fighter Pilots Who Made History

       C. Women during the Second World War               D. Fighting the Germans

 Question 35. The fact that Litvyak had her first solo flight when she was only 15 implies that __________.

       A. it was a risky thing to do                                     B. she loved danger

       C. she had a natural talent for flying                        D. her flying club was the best in the world

 Question 36. What did Budanova do before she become a fighter pilot?

       A. She worked at a flying club.                                B. She was a Russian officer.

       C. She worked as a non-military pilot.                    D. She shot down German planes.

 Question 37. The word 'solo' in paragraph 2 is opposite meaning to ________.

       A. done by one person alone                                    B. successful                                             

       C. done by more than one person                             D. single

 Question 38. The phrase "a second" in paragraph 1 refers to _______.

       A. the Second World War                                                                                B. a second German plane          

       C. a second Russian plane                                       D. a fighter pilot

 Question 39. The word "them" in paragraph 1 refers to_______.

       A. fighter pilots                                                        B. well-known fighter pilots

       C. some Russian women                                          D. women    

 Question 40. Which of the following is NOT true about Budanova and Uitvyak, according to the text?

       A. They died in their twenties.

       B. They died when the Second World War was over.

       C. They were talented and successful female fighter pilots in the Soviet Air Force.

       D. They are considered two of the world's most famous female fighter pilots.

6 giờ trước (20:30)

Số số hạng trong dãy là x-6+1=x-5(số)

Tổng của dãy số là (x+6)x(x-5):2

Theo đề, ta có:

\(\left(x+6\right)\times\dfrac{\left(x-5\right)}{2}=195\)

=>\(\left(x+6\right)\times\left(x-5\right)=390\)

=>\(x^2+x-420=0\)

=>(x+21)(x-20)=0

=>\(\left[{}\begin{matrix}x=-21\left(loại\right)\\x=20\left(nhận\right)\end{matrix}\right.\)

Vậy: x=20

\(6+7+8+9+...+x=195\)

\(1+2+3+...+x-\left(1+2+3+4+5\right)=195\)

\(\dfrac{x\left(x+1\right)}{2}-\left(1+2+3+4+5\right)=195\)

\(\dfrac{x\left(x+1\right)}{2}=210\)

\(x\left(x+1\right)=420\)

\(x\cdot x+x=420\)

\(x=420\)

6 giờ trước (20:36)

Đặt số nam trong lớp là x và số nữ là y.

Theo điều kiện đầu tiên: mỗi nhóm có 4 nam và 3 nữ, thừa 1 bạn nữ. Ta có thể viết thành phương trình: 4x = 3y + 1 (1)

Theo điều kiện thứ hai: mỗi nhóm có 5 nam và 4 nữ, đúng số lượng. Ta có thể viết thành phương trình: 5x = 4y (2)

Giải hệ phương trình (1) và (2):

Từ (2) suy ra x = 4/5y Thay x vào (1) ta có: 4(4/5y) = 3y + 1 Giải phương trình trên ta có: y = 8

Thay y vào (2): 5x = 4*8 => x = 6

Vậy, số nam trong lớp là 6 và số nữ là 8.

 

(´▽`ʃ♡ƪ) Cho xin một like nha !!!

9 giờ trước (18:05)

Số học sinh lớp 5A là:

21+24-12=33(bạn)

9 giờ trước (18:07)

tk ạ
Số học sinh lớp 5A là:

21+24-12=33(bạn)

Đáp số: 33 bạn học sinh    
9 giờ trước (17:42)

\(\left(5:5\right)+6+7+8+9+10:\left(10\cdot40\right)\)

=\(1+6+7+8+9+10:400\)

=\(1+6+7+8+9+\dfrac{10}{400}\)

=\(1+6+7+8+9+\dfrac{1}{40}\)

=\(31+\dfrac{1}{40}\)

=\(\dfrac{1240}{40}+\dfrac{1}{40}\)

=\(\dfrac{1241}{40}\)

Dấu . là dấu x nha em!

7 giờ trước (19:48)

cảm ơn cô nhé