Question

Из одного города одновременно в противоположных направлениях выехал велосипедист и вышел пешеход . Скорость пешехода 6 км/ч, скорость велосипедиста в 2 раза больше. Через какое время расстояние между ними будет 54 км?

Answer 1

1) 6*2=12(км/ч) такая скорость велосипедиста.
2) 12+6=18(км/ч) такая общая скорость.
3)54:18=3(ч) столько времени 

Answer 2

6 км в час умножить на 2

Answer 3

Problem Analysis

We are given that a cyclist and a pedestrian start from the same city simultaneously and travel in opposite directions. The pedestrian's speed is 6 km/h, while the cyclist's speed is twice that of the pedestrian. We need to determine the time it takes for the distance between them to be 54 km.

Solution

Let's assume the speed of the pedestrian is v km/h. According to the problem, the speed of the cyclist is twice that of the pedestrian, so the cyclist's speed is 2v km/h.

We can use the formula distance = speed × time to find the time it takes for the distance between them to be 54 km.

Let's denote the time it takes for the distance between them to be 54 km as t hours.

The distance traveled by the pedestrian in t hours is 6t km, and the distance traveled by the cyclist in t hours is 2vt km.

According to the problem, the sum of the distances traveled by the pedestrian and the cyclist is equal to 54 km:

6t + 2vt = 54

We can solve this equation to find the value of t.

Calculation

Let's solve the equation 6t + 2vt = 54 for t:

6t + 2vt = 54

Factoring out t:

t(6 + 2v) = 54

Dividing both sides by 6 + 2v:

t = 54 / (6 + 2v)

Substituting v = 6 (since the pedestrian's speed is 6 km/h):

t = 54 / (6 + 2(6))

Simplifying:

t = 54 / (6 + 12)

t = 54 / 18

t = 3

Therefore, it will take 3 hours for the distance between the cyclist and the pedestrian to be 54 km.

Answer

The distance between the cyclist and the pedestrian will be 54 km after 3 hours.