Question

Собственная скорость теплохода 12,5 км/ч, а скорость реки 2,5 км/ч. Сколько времени продолжалась прогулка на теплоходе, если теплоход прошел от пристани по течению реки 30 км и, не останавливаясь, вернулся назад.

Answer 1

12,5+2,5=15-скорость по теч.30/15=2 часа по течению 12,5-2,5=10-скорость против теч.30/10=3 часа против течения 3+2=5 часов всего

Answer 2

Calculation of the Duration of the Boat Trip

To calculate the duration of the boat trip, we need to consider the speed of the boat and the speed of the river.

Given: - Boat speed: 12.5 km/h - River speed: 2.5 km/h - Distance traveled downstream: 30 km

To calculate the duration of the boat trip, we can use the formula:

Time = Distance / Speed

1. Time taken to travel downstream: - Distance: 30 km - Speed: Boat speed + River speed = 12.5 km/h + 2.5 km/h = 15 km/h - Time = 30 km / 15 km/h = 2 hours

2. Time taken to travel upstream: - Distance: 30 km (same as downstream) - Speed: Boat speed - River speed = 12.5 km/h - 2.5 km/h = 10 km/h - Time = 30 km / 10 km/h = 3 hours

3. Total duration of the boat trip: - Time taken downstream + Time taken upstream = 2 hours + 3 hours = 5 hours

Therefore, the boat trip lasted for 5 hours.