Người ta thả một số lá bèo vào một hồ nước. Sau 10 giờ, số lượng lá bèo sẽ sinh sôi kín cả mặt hồ. Biết rằng sau mỗi giờ, số lượng lá bèo tăng gấp 10 lần số lượng lá bèo trước đó và tốc độ tăng không đổi. Sau ít nhất mấy giờ thì số lá bèo phủ kín hơn một phần tư hồ (làm tròn kết quả đến hàng đơn vị)?

Tốc độ dài của một điểm trên kim giây cách trục quay 2cm của một đồng hồ là

Đọc đoạn tư liệu sau đây:

Các nguyên tắc hoạt động của Liên hợp quốc

1. Bình đẳng chủ quyền của tất cả các quốc gia thành viên;

2. Tôn trọng toàn vẹn lãnh thổ và độc lập chính trị quốc gia;

3. Cấm đe dọa sử dụng vũ lực hoặc sử dụng vũ lực trong quan hệ quốc tế;

4. Không can thiệp vào công việc nội bộ của các nước;

5. Tôn trọng các nghĩa vụ quốc tế và luật pháp quốc tế;

6. Giải quyết các tranh chấp quốc tế bằng biện pháp hòa bình.

(Theo Điều 2, Hiến chương Liên hợp quốc năm 1945)

Thị trường có bao nhiêu chức năng cơ bản?

In ____ to your regular duties, you can do many other things around the home that would benefit your family.

Có bao nhiêu loại chủ thể kinh tế?

Read the following passage about Singapore Science Centre and mark the letter A, B, C, or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.

The Singapore Science Centre, situated on a sprawling six-hectare site in Jurong, offers a captivating way to explore the wonders of science and technology. Here, visitors can engage with interactive exhibits that make learning both fun and memorable. Clap your hands, and colorful bulbs will light up; spin a wheel, and it will activate a fan. This engaging environment sparks curiosity and fuels the imagination of both children and adults.

The centre boasts more than four hundred exhibits across various fascinating topics, including solar radiation, communication, electronics, mathematics, nuclear energy, and evolution. These exhibits are designed to foster interest in science and technology among the public, making the centre a hub for educational exploration.

Notably, it is the first science centre to be established in Southeast Asia. Officially opened in 1977, the centre now welcomes an average of 1,200 visitors daily, highlighting its enduring popularity and educational value.

The exhibits are thoughtfully arranged across four main galleries: the Lobby, Physical Sciences, Life Sciences, and Aviation. To ensure a fresh and engaging experience, the exhibits are renewed annually, encouraging repeat visits. Visitors are encouraged to interact with the exhibits, as opposed to traditional “hands-off” policies in most museums. Here, pushing buttons, turning cranks, or pedaling mechanisms are all part of the fun and learning experience.

The Discovery Centre, added in 1985, is specially designed for children aged three to twelve, providing an exciting space for young minds to explore and experiment. Most recently, a stone-age exhibit was introduced, showcasing extinct animals and early human life, offering insights into prehistoric times.

With its interactive displays and immersive environment, the Singapore Science Centre continues to inspire a love for science and discovery, making it an unforgettable destination for learners of all ages.

Which of the following is NOT mentioned as one of the topics covered in the exhibits in paragraph 2?

Trong hệ tuần hoàn của thú, máu ở thành phần nào dưới đây giàu O₂?

Một trong những trách nhiệm của chủ thể sản xuất là gì?

The word "inconsequential" in paragraph 1 is closest in meaning to ______.

Read thefollowing passage and mark the letter A, B, C or D on your answer sheet to indicate the option that bestfits each of the numbered blanksfrom 18 to 22.

Peer pressure, (18) ________, can have both positive and negative effects. For instance, when surrounded by motivated peers, (19) ________. Positive peer pressure can be a great motivator, as peers who excel in academics or extracurricular activities can inspire others to follow suit. However, peer pressure can also lead to negative outcomes. The influence of friends who engage in risky behaviors, such as skipping school or using substances, can encourage others to make poor decisions. Studies have shown that teenagers are more likely to take risks in the presence of their peers because they feel more confident when surrounded by others.

While peer pressure is often associated with negative behavior,  (20) ________. For example, students may be encouraged to excel in their studies or participate in volunteer activities due to the positive influence of their peers. However, it is important to develop strong decision-making skills and self-confidence (21) ________.

Parents and educators play a key role in helping young people navigate peer pressure. By teaching young people how to recognize both positive and negative peer pressure, and how to make independent, thoughtful decisions, parents and educators can help ensure that students thrive in a healthy, supportive environment. Encouraging open communication, providing advice on how to stay true to one's values, and helping students develop self-confidence are all crucial aspects of this process.

In conclusion, peer pressure is a powerful influence. (22) ________, teenagers can succeed and grow in a positive social environment.

Cuối thế kỉ XVIII, chủ nghĩa tư bản

Giá trị lớn nhất của \(F(x;y) = 5x - 3y\), với điều kiện \(\left\{ \begin{array}{l}x \ge 0\\0 \le y \le 5\\x + y - 2 \ge 0\\3x - y \le 6\end{array} \right.\) 

Phương trình \(\cos x=\frac{1}{2}\) có nghiệm là: