Question

ТЕПЛОХОД ПРОХОДИТ ПО ТЕЧЕНИЮ РЕКИ ДО ПУНКТА НАЗНАЧЕНИЯ 160 КМ И ПОСЛЕ СТОЯНКИ ВОЗВРАЩАЕТСЯ В ПУНКТ ОТПРАВЛЕНИЯ НАЙДИТЕ СКОРОСТЬ ТЕЧЕНИЯ ЕСЛИ СКОРОСТЬ ТЕПЛОХОДА В НЕПОДВИЖНОЙ ВОДЕ РАВНА 18 КМ ЧАС СТОЯНКА ДЛИТСЯ 2 ЧАСА А В ПУНКТ ОТПРАВЛЕНИЯ ТЕПЛОХОД ВОВРАЩАЕТСЯ РОВНО ЧЕРЕЗ 20 ЧАСОВ ПОСЛЕ ОТПЛЫТИЯ ИЗ НЕГО ОТВЕТ ДАЙТЕ В КИЛОМЕТРАХ

Answer 1

Х км/ч - скорость течения
(18+х) - скорость по течению
(18-х) - скорость против течения
t=S:v
160/(18-х) - время в пути против течения
160/(18+х)- время по течению
20час-2час=18час - всего в пути
160/(18-х) +160/(18+х)=18, общий знаменатель (18+х)(18-х)
2880+160х+2880-160х=5832-18х²
18х²=5832-5760
18х²=72
х²=72:18
х²=4
х=2(км/час) - скорость течения

Answer 2

Скорость течения = х (км/ч)
Скорость по течению = (18 + х) км/ч
Скорость против течения = (18 - х) км/ч
Время по течению = 160 / (х + 18) км
Время против течения = 160 /(18 - Х) км
Время в пути = 20 - 2 = 18(ч)
Составим уравнение:
160 / (18 +х) + 160 /(18 - х)  = 18
160 *(18 - х) + 160 * (18 + х)  + 2(18= 18 (18^2 - х^2)
2880 - 160х + 2880 + 160х = 18(324 -х^2)
5760 = 5832 - 18x^2
18x^2 = 5832 - 5760
18x^2 = 72
x^2 = 4
x = 2
Ответ: 2км/ч - скорость течения реки.

Answer 3

Calculation of River Current Speed

To find the speed of the river current, we can use the formula:

Speed of the river current = Distance traveled by the boat / Time taken to travel that distance

Given information: - Distance traveled by the boat from the point of departure to the destination = 160 km - Time taken to travel from the point of departure to the destination = 20 hours - Time taken for the boat to return from the destination to the point of departure = 2 hours - Speed of the boat in still water = 18 km/h

Let's calculate the speed of the river current using the given information.

1. Calculate the total time taken for the round trip: - Time taken from the point of departure to the destination = 20 hours - Time taken from the destination to the point of departure = 2 hours - Total time taken for the round trip = 20 hours + 2 hours = 22 hours

2. Calculate the total distance traveled during the round trip: - Distance traveled from the point of departure to the destination = 160 km - Distance traveled from the destination to the point of departure = 160 km - Total distance traveled during the round trip = 160 km + 160 km = 320 km

3. Calculate the speed of the river current: - Speed of the boat in still water = 18 km/h - Let's assume the speed of the river current as 'x' km/h - Speed of the boat downstream (from the point of departure to the destination) = Speed of the boat in still water + Speed of the river current = 18 km/h + x km/h - Speed of the boat upstream (from the destination to the point of departure) = Speed of the boat in still water - Speed of the river current = 18 km/h - x km/h

According to the given information, the boat takes 20 hours to travel from the point of departure to the destination and 2 hours to return. Since the speed of the boat