120+ 126=246 (kg). 40×2=80 (kg). 246-80= 166 (kg). 166÷4=4 1.5 (kg). A: The average weight of four people is 4 1.5 kg.
From the meaning of the question, 120+ 126=246 kg is the total weight of A, B, C, D, C and D. It is known that the average weight of C and D is 40 kg, that is, the total weight of C and D is 40×2=80 kg. Then a, b, c and d,
The Function and Significance of Mathematics
1. Solving practical problems: Mathematics is a tool that can help us solve many practical problems, such as calculating costs, solving geometric problems, making statistical analysis and forecasting.
2. Cultivate thinking ability: Mathematics is an effective way to cultivate thinking ability. By studying mathematics, we can exercise our logical reasoning ability, abstract thinking ability, imagination and creativity, and improve our ability to solve problems.
3. Promote the study of other disciplines: Mathematics is the foundation of many other disciplines, such as physics, chemistry and computer science. Mastering the basic knowledge of mathematics is helpful for us to better understand and apply the knowledge of these subjects.
4. Application in society: Mathematics has a wide range of applications in society, such as finance, economy, engineering, science and medicine. In these fields, mathematics is used to analyze and solve problems, which provides more convenience and guarantee for our lives.