Question

Из двух городов А и В одновременно вышли два пешехода.Когда они встретились в точке С,то оказалось,что одному пешеходу потребуется 4ч 30 мин,чтобы прийти в точку А. А второму до В идти 2 часа. Определите скорость пешеходов если АВ= 30 км

Answer 1

4,5x + 2y = 30
x = $\frac{30}{4,5 + t}$
y = $\frac{30}{2 + t}$
4,5 * $\frac{30}{4,5 + t}$ + 2 * $\frac{30}{2 + t}$ = 30     | * (4,5 + t) * (2 + t)
270 + 135t + 270 + 60t = 30t² + 195t + 270
30t² - 270 = 0     | : 30
t² - 9 = 0
t = -3 не подходит, т. к. t > 0
t = 3
x = $\frac{30}{7,5}$ = 4 (км/ч)
y = $\frac{30}{5}$ = 6 (км/ч)

Answer 2

Problem Analysis

Two pedestrians, starting from points A and B, meet at point C. One pedestrian takes 4 hours and 30 minutes to walk from point C to point A, while the other takes 2 hours to walk from point C to point B. The distance between points A and B is 30 km. We need to determine the speed of the pedestrians.

Solution

Let's denote the speed of the first pedestrian as v1 and the speed of the second pedestrian as v2.

We know that time = distance / speed.

For the first pedestrian: - Time taken to walk from C to A = 4 hours 30 minutes = 4.5 hours - Distance from C to A = 30 km - Therefore, 4.5 = 30 / v1 => v1 = 30 / 4.5

For the second pedestrian: - Time taken to walk from C to B = 2 hours - Distance from C to B = 30 km - Therefore, 2 = 30 / v2 => v2 = 30 / 2

Calculation

Let's calculate the speeds of the pedestrians.

For the first pedestrian: v1 = 30 / 4.5 = 6.67 km/h

For the second pedestrian: v2 = 30 / 2 = 15 km/h

Answer

So, the speed of the first pedestrian is 6.67 km/h and the speed of the second pedestrian is 15 km/h.