Question

Решите задачу,составив уравнение. Из города в поселок вышел пешеход со скоростью 4,5 км/ч через два часа вслед за ним выехал велосипедист со скоростью 18 км/ч. Через какое время после своего выезда велосипедист догонит пешехода? Плиз помогите!!!

Answer 1

Расстояние, которое пройдет до встречи пешеход 4 1\2х(Х+2) , а велосипедист проедет до встречи 18Х. Поскольку он догонит пешехода, расстояние они пройдут одинаковое, т.е. 4 1\2 х (Х+2)=18Х, откуда
13 1\2 Х= 9 и, следовательно, Х=2\3 часа, т.е. 40 минут

Answer 2

Formulating the Problem

To solve this problem, we need to determine the time it will take for the cyclist to catch up to the pedestrian. The pedestrian starts walking at a speed of 4.5 km/h, and the cyclist starts riding at a speed of 18 km/h, two hours after the pedestrian.

Solution

Let's denote: - t as the time it takes for the cyclist to catch up to the pedestrian. - d as the distance covered by the pedestrian before the cyclist starts.

The distance covered by the pedestrian before the cyclist starts is given by the formula: d = 4.5 km/h * 2 h = 9 km.

Now, we can use the formula: distance = speed * time.

The time it takes for the cyclist to catch up to the pedestrian can be calculated using the formula: 18 km/h * t = 9 km + 4.5 km/h * t.

Solving for t: 18t = 9 + 4.5t, 18t - 4.5t = 9, 13.5t = 9, t = 9 / 13.5, t = 0.6667 hours.

Answer

So, the cyclist will catch up to the pedestrian approximately 0.6667 hours after the cyclist's departure.