Question

Мальчик прошёл 3 км по шоссе и 6 км по полю. Весь путь занял у него 2 ч. По шоссе он шёл со скоростью на 2 км/ч большей, чем по полю. С какой скоростью шёл мальчик по полю? Ответ дайте в км/ч.

Answer 1

Пусть х км.ч-шёл по полютогда по шоссе-х+2 3/(х+2)+6/х=23х+6(х+2)=2х(х+2)3х+6х+12=2х^2+4x-2х^2-4x+9x+12=02х^2-5x-12=0D=25+96=121x1=4x2=-1,5(не подх)если нужно подробно, напишу ответ 4  км.ч

Answer 2

3.5 км в час шел по полю

Answer 3

Problem Analysis

We are given that a boy walked 3 km on a highway and 6 km in a field. The total time taken for the entire journey was 2 hours. The boy walked on the highway at a speed 2 km/h faster than in the field. We need to find the speed at which the boy walked in the field.

Solution

Let's assume the speed of the boy in the field is x km/h. Since the boy walked 3 km on the highway, the time taken for this part of the journey can be calculated using the formula time = distance / speed. Therefore, the time taken on the highway is 3 / (x + 2) hours.

Similarly, the time taken for the field part of the journey can be calculated as 6 / x hours.

According to the problem, the total time taken for the entire journey is 2 hours. Therefore, we can write the equation:

3 / (x + 2) + 6 / x = 2

To solve this equation, we can multiply both sides by x(x + 2) to eliminate the denominators:

3x + 6(x + 2) = 2x(x + 2)

Simplifying the equation:

3x + 6x + 12 = 2x^2 + 4x

8x + 12 = 2x^2 + 4x

2x^2 - 4x - 8x - 12 = 0

2x^2 - 12x - 12 = 0

Now, we can solve this quadratic equation to find the value of x.