Question

Помогите с задачей 5-го класса:С аэродрома вылетел вертолёт со скоростью 210 км/ч. Через 2 ч.с этого же аэродрома вылетел за вертолётом самолет,КОТОРЫЙ ЧЕРЕЗ 3 ЧАСА После своего вылета перегнал самолёт на 840 км.найдите скорость самолёта

Answer 1

210 * 2 = 420 км - пролетел вертолёт за 2 часа.
420 + 840 = 1260 км - пролетел самолёт за 3 часа.
1260 : 3 = 420 км/ч - скорость самолёта.

Answer 2

Task Analysis

The helicopter took off from the aerodrome at a speed of 210 km/h. After 2 hours, a plane took off from the same aerodrome and caught up with the helicopter 3 hours after its own takeoff. We need to find the speed of the plane.

Solution

To solve this problem, we can use the formula: distance = speed × time

Let's denote the speed of the plane as P and the speed of the helicopter as H.

The helicopter travels for 2 hours at a speed of 210 km/h, so the distance covered by the helicopter is: distance_helicopter = 210 km/h × 2 h

The plane catches up with the helicopter after 3 hours and travels a total distance of 840 km, so the distance covered by the plane is: distance_plane = P × 3 h

Since the plane catches up with the helicopter, the distances covered by both the plane and the helicopter are equal: distance_helicopter = distance_plane

We can use this information to solve for the speed of the plane.

Calculations

Let's calculate the distance covered by the helicopter and the plane, and then solve for the speed of the plane.

The distance covered by the helicopter is: distance_helicopter = 210 km/h × 2 h = 420 km

Since the plane catches up with the helicopter after 3 hours, the distance covered by the plane is: distance_plane = P × 3 h

Given that the plane covers a total distance of 840 km, we have: distance_plane = 840 km

Equating the distances covered by the helicopter and the plane: 420 km = 840 km

Now, we can solve for the speed of the plane: P × 3 h = 840 km P = 840 km / 3 h

Answer

The speed of the plane is: P = 840 km / 3 h

Let's calculate the speed of the plane: P = 840 km / 3 h = 280 km/h

Therefore, the speed of the plane is 280 km/h.