Question

Две девочки одновременно побежали навстречу друг другу по спортивной дорожке , для на которой 420 м. Когда они встретились , первая пробежала на 60 м больше , чем вторая . С какой скоростью бежала каждая девочка , если они встретились через 30 сек ? СРОЧНО даю 20 баллов !

Answer 1

Если бы вторая девочка пробежала еще 60 метров, то обе девочки пробежали бы одинаковый путь
420+60=480 м -БЫЛ БЫ путь двух девочек
480:2=240 м-БЫЛ БЫ путь каждой из девочек, но на самом деле это путь первой девочки
420-240=180 м -реальный путь второй девочки
скорость первой девочки:
240/30=8 м/с
скорость второй девочки:
180/30=6 м/с

Answer 2

Problem Analysis

Two girls are running towards each other on a 420-meter long track. When they meet, the first girl has run 60 meters more than the second girl. We need to find the speed at which each girl was running if they met after 30 seconds.

Solution

Let's denote the speed of the first girl as x meters per second and the speed of the second girl as y meters per second. We can use the formula distance = speed * time to solve this problem.

When they meet, the total distance covered by both girls is 420 meters. We can set up the following equation based on the given information: 1. 30x + 30y = 420 (since they meet after 30 seconds) 2. x = y + 60 (the first girl runs 60 meters more than the second girl when they meet)

We can use these equations to solve for the speeds of the two girls.

Solving the Equations

Substitute the value of x from the second equation into the first equation: 1. 30(y + 60) + 30y = 420 2. 30y + 180 + 30y = 420 3. 60y + 180 = 420 4. 60y = 240 5. y = 4

Now that we have found the value of y, we can find the value of x using the second equation: 1. x = 4 + 60 2. x = 64

Conclusion

The speed of the first girl is 64 meters per second and the speed of the second girl is 4 meters per second.