Question

Андрей идёт на лыжах со скоростью 18 км/час, а Борис-со скоростью 15 км/час. Сближаютсялыжники или удаляются друг от друга и с какой скоростью, если они двигаются:1) в противоположных направлениях от лыжной базы;2)навстречу друг другу с двух лыжных баз;3)от базы в одном направлении и Борис(15 км/час) идёт за Андреем(18 км/час);4)от базы в одном направлении и Андрей(18 км/час) идёт за Борисом(15 км/час).

Answer 1

1) удаляются со скоростью 18+15=33 км/час

2) сближаются со скоростью 18+15=33 км/час

3) Борис отстает от Андрея на 18-15=3 км/час

4) Андрей опережает Бориса на 18-15=3 км/час

 

Answer 2

Analysis and Solution

To determine whether the skiers are approaching or moving away from each other, we need to compare their speeds and directions. Let's analyze each scenario:

1) When the skiers are moving in opposite directions from the ski base: - Andrey's speed: 18 km/h - Boris's speed: 15 km/h

In this case, the skiers are moving away from each other. To find the relative speed at which they are moving apart, we can subtract Boris's speed from Andrey's speed: 18 km/h - 15 km/h = 3 km/h. Therefore, the skiers are moving away from each other at a speed of 3 km/h.

2) When the skiers are moving towards each other from two different ski bases: - Andrey's speed: 18 km/h - Boris's speed: 15 km/h

In this scenario, the skiers are moving towards each other. To find the relative speed at which they are approaching each other, we can add their speeds: 18 km/h + 15 km/h = 33 km/h. Therefore, the skiers are approaching each other at a speed of 33 km/h.

3) When the skiers are moving in the same direction from the ski base, with Boris following Andrey: - Andrey's speed: 18 km/h - Boris's speed: 15 km/h

In this case, the skiers are moving in the same direction. To find the relative speed at which they are moving, we can subtract Boris's speed from Andrey's speed: 18 km/h - 15 km/h = 3 km/h. Therefore, the skiers are moving in the same direction with a relative speed of 3 km/h.

4) When the skiers are moving in the same direction from the ski base, with Andrey following Boris: - Andrey's speed: 18 km/h - Boris's speed: 15 km/h

In this scenario, the skiers are moving in the same direction. To find the relative speed at which they are moving, we can subtract Boris's speed from Andrey's speed: 18 km/h - 15 km/h = 3 km/h. Therefore, the skiers are moving in the same direction with a relative speed of 3 km/h.

To summarize: - When the skiers are moving in opposite directions, they are moving away from each other at a speed of 3 km/h. - When the skiers are moving towards each other from two different ski bases, they are approaching each other at a speed of 33 km/h. - When the skiers are moving in the same direction, either with Boris following Andrey or with Andrey following Boris, they are moving in the same direction with a relative speed of 3 km/h.

Please let me know if there is anything else I can help you with!