Question

Из Иецавы в Ригу одновременно навстречу друг другу выехали два велосипедиста со скоростью 15км/ч и 17км/ч.Через час между ними было 10км.Сколько милометров из Ецавы до Риги?

Answer 1

1) 10 + 17 + 15 = 42 (км)

Answer 2

Problem Analysis

To solve this problem, we can use the concept of relative speed. We know the speeds of the two cyclists and the distance between them after an hour. We can use this information to calculate the distance between the two cities.

Solution

Let's calculate the relative speed of the two cyclists: - Cyclist 1 speed = 15 km/h - Cyclist 2 speed = 17 km/h

The relative speed of the two cyclists is the sum of their individual speeds: Relative speed = 15 km/h + 17 km/h = 32 km/h

Now, we know that after one hour, the distance between them was 10 km. We can use the formula: distance = speed * time to find the total distance between the two cities.

Let's denote the distance between the two cities as x.

Using the formula distance = speed * time, we can write the equation: 10 km = 32 km/h * 1 h

Solving for x: x = 32 km/h * t, where t is the time taken to cover the distance between the two cities.

Calculation

To find the time taken to cover the distance between the two cities, we can use the formula: time = distance / speed

Substituting the values: t = x / 32

Now, we know that the time taken by the two cyclists to cover the distance between the two cities is the same. Therefore, we can write two equations based on their individual speeds: - t = x / 15 (for cyclist 1) - t = x / 17 (for cyclist 2)

Solving for x

Equating the two expressions for t: x / 15 = x / 17

Solving for x: x = (15 * 17) / (17 - 15) x = 255 / 2 x = 127.5 km

Answer

The distance from Jelgava to Riga is 127.5 kilometers.