Question

З двох будинків відстань між якими 20км. Одночасно назустріч один одному вийшли двоє друзів. Перший рухався зі швидкістю 5 км/год,а другий 7 км/год. Через скільки годин друзі зустрілися?

Answer 1

Ответ:

Перший подолав шлях 5х км, а другий 7х км, де х - час.

Запишемо рівняння

5х + 7х =20 км

12х=20

х=20/12

х = 1 8/12= 1 2/3 год

2/3 години це 40 хвилин, тож хлопці зустрілися через 1 год 40 хв

Answer 2

#### Problem Analysis We have two friends who start walking towards each other from two different buildings. The distance between the buildings is 20 km. The first friend walks at a speed of 5 km/h, while the second friend walks at a speed of 7 km/h. We need to determine how many hours it will take for the friends to meet. #### Solution To solve this problem, we can use the formula: **Time = Distance / Speed** Let's calculate the time it will take for the friends to meet. The first friend walks at a speed of 5 km/h, so the time taken by the first friend to cover the distance of 20 km is: **Time taken by the first friend = Distance / Speed = 20 km / 5 km/h = 4 hours**. Similarly, the second friend walks at a speed of 7 km/h, so the time taken by the second friend to cover the distance of 20 km is: **Time taken by the second friend = Distance / Speed = 20 km / 7 km/h ≈ 2.857 hours**. Since both friends started walking at the same time, we need to find the time it takes for them to meet. Since the second friend takes less time to cover the distance, we can use the time taken by the second friend as the answer. Therefore, the friends will meet after approximately **2.857 hours**. Note: The actual time may vary slightly depending on the exact decimal value of the calculation. I hope this helps! Let me know if you have any further questions.