Question

из пункта А в пункт В расстояние между которыми 60 км,одновременно выехали автомобилист и велосипедист.За час автомобилист проезжает на 40 км больше чем велосипедист.Определите скорость велосипедиста,если известно что он прибыл в пункт В на 2 часа позже автомобилиста.Ответ дайте в км/с

Answer 1

Пусть x- скорость велосипедиста, тогда x+40-автомобиля.

Найдём разность времени их поездки:

60/x-60/(x+40)=2

2400/(x^2+40x)=2

2400=2x^2+80x

x^2+40x-1200=0

По теореме Виета:

x1+x2=-40 x1*x2=-1200

x1=-60 x2=20

Первый не подходит, т.к. скорокть не может быть отрицательной.

 

Answer 2

Problem Analysis

We are given that the distance between point A and point B is 60 km. An automobile driver and a cyclist simultaneously start from point A. In one hour, the automobile driver travels 40 km more than the cyclist. We need to determine the speed of the cyclist, given that the cyclist arrives at point B 2 hours later than the automobile driver.

Solution

Let's assume the speed of the cyclist is v km/h. Since the automobile driver travels 40 km more than the cyclist in one hour, the speed of the automobile driver is v + 40 km/h.

We can use the formula distance = speed × time to calculate the time taken by each of them to reach point B.

The time taken by the automobile driver to reach point B is given by: time taken by automobile driver = distance / speed of automobile driver

The time taken by the cyclist to reach point B is given by: time taken by cyclist = distance / speed of cyclist

We are given that the cyclist arrives at point B 2 hours later than the automobile driver. Therefore, we can write the equation: time taken by cyclist = time taken by automobile driver + 2

Substituting the values, we get: distance / (v + 40) = distance / v + 2

To solve for v, we can cross-multiply and simplify the equation: distance × v = distance × (v + 40) + 2 × distance × v

Simplifying further: distance × v = distance × v + distance × 40 + 2 × distance × v

Cancelling out the common terms: 0 = distance × 40

Since the distance is not zero, we can conclude that there is no solution for this equation. Therefore, there is no valid speed for the cyclist that satisfies the given conditions.

Answer

There is no valid speed for the cyclist that satisfies the given conditions.