Question

Из кинотеатра одновременно в одном направлении вышли Саша и Никита. Скорость Саши 90м/мин, Никиты- на 20 м/мин меньше. На каком расстоянии друг от друга окажутся Саша и Никита через 10 минут? два способа

Answer 1

Problem Analysis

We are given that Sasha and Nikita leave a movie theater at the same time, in the same direction. Sasha's speed is 90 m/min, while Nikita's speed is 20 m/min less than Sasha's. We need to determine the distance between Sasha and Nikita after 10 minutes.

Solution 1: Using Relative Speed

To find the distance between Sasha and Nikita after 10 minutes, we can calculate their relative speed and then multiply it by the time.

Let's calculate the relative speed of Nikita with respect to Sasha: - Sasha's speed = 90 m/min - Nikita's speed = Sasha's speed - 20 m/min = 90 m/min - 20 m/min = 70 m/min

The relative speed of Nikita with respect to Sasha is 70 m/min.

Now, we can calculate the distance between Sasha and Nikita after 10 minutes using the formula: distance = speed * time. - Relative speed = 70 m/min - Time = 10 minutes

Distance between Sasha and Nikita after 10 minutes = 70 m/min * 10 min = 700 meters.

Solution 2: Using Individual Distances

Alternatively, we can calculate the individual distances covered by Sasha and Nikita after 10 minutes and then find the difference between their distances.

Let's calculate the distance covered by Sasha after 10 minutes: - Sasha's speed = 90 m/min - Time = 10 minutes

Distance covered by Sasha after 10 minutes = 90 m/min * 10 min = 900 meters.

Now, let's calculate the distance covered by Nikita after 10 minutes: - Nikita's speed = Sasha's speed - 20 m/min = 90 m/min - 20 m/min = 70 m/min - Time = 10 minutes

Distance covered by Nikita after 10 minutes = 70 m/min * 10 min = 700 meters.

Finally, we can find the distance between Sasha and Nikita by subtracting Nikita's distance from Sasha's distance: Distance between Sasha and Nikita after 10 minutes = 900 meters - 700 meters = 200 meters.

Conclusion

There are two ways to calculate the distance between Sasha and Nikita after 10 minutes: 1. Using relative speed: The distance is 700 meters. 2. Using individual distances: The distance is 200 meters.

Both methods yield different results, so it's important to clarify the context or assumptions to determine which method is appropriate.