Formula: At the moment of meeting, all the distances have passed. Divide by the sum of the speeds and you get the time. For example, A and B walk in opposite directions from two places 120km apart. Party A's speed is 40km/h and Party B's speed is 20 km/h. How long did they meet?
At the moment we met, the distance disappeared. That is, the distance traveled by Party A and Party B is exactly 120km. Divide by the sum of the speeds and you get the time. That is, the total speed of Party A and Party B is 40+20 = 60 (km/h), so the meeting time is 120 ÷ 60 = 2 (h).
Distance problem (catch-up) formula: slow birds fly first, fast birds chase after. Divide the distance you go first by the speed difference, and the time is right.
Brother and sister go to town from home. My sister walked at a speed of 3 km/h, and after walking for 2 hours, my brother rode at a speed of 6 km/h. When will he catch up? The distance ahead is 3×2=6 (km) speed difference, that is, 6-3 = 3 (km/h). So the catch-up time is: 6 ÷ 3 = 2 (hours).
The benefits of studying mathematics are as follows:
1. Mathematics can make your brain smarter and increase the rigor of thinking.
2. Mathematics is a basic subject. If you can't learn math well, you can't learn anything well. No matter what you want to learn, you must have a foundation in mathematics.
3. Mathematical knowledge runs through our life, which can be said to be everywhere. We live with these mathematical knowledge unconsciously every day.
Mathematics is the study of all quantitative relations and spatial position relations in the world. It can be said that without mathematics, nothing can move.