Question

В 16 ч 40 мин от пристани отошла моторная лодка . В 18 ч 40мин в этом же направление отчалил теплоход. через какое время теплоход догонит лодку, если её скорость, если 15 км\ч, а скорость теплохода 30 км\ч

Answer 1

Надем разницу по времени между отправлениями лодки и теплохода
18:40 - 16:40 = 2 ч
найдем расстояние между лодкои и теплоходом в момент начала движения последнего
15*2=30 км
 вспомним формулу для движения вдогонку
$S=(v_2-v_1)*t$
подставляем известные значения и находим время их встречи
t=30:(30-15)= 2 ч
Ответ: через 2 ч теплоход догонит лодку

Answer 2

To find out how long it will take for the ship to catch up with the motorboat, we need to calculate the time it takes for the ship to cover the distance between them.

Given: - The motorboat departed from the pier at 16:40. - The ship departed from the same pier at 18:40. - The speed of the motorboat is 15 km/h. - The speed of the ship is 30 km/h.

Calculating the Time Difference:

To calculate the time difference between the departure of the motorboat and the ship, we subtract the departure time of the motorboat from the departure time of the ship.

- Time difference = 18:40 - 16:40 = 2 hours

Calculating the Distance:

To calculate the distance between the motorboat and the ship, we need to know the distance covered by the motorboat during the 2-hour time difference.

- Distance covered by the motorboat = speed * time = 15 km/h * 2 h = 30 km

Calculating the Time for the Ship to Catch Up:

Now that we know the distance between the motorboat and the ship is 30 km, we can calculate the time it will take for the ship to catch up with the motorboat.

- Time = distance / relative speed = 30 km / (30 km/h - 15 km/h) = 30 km / 15 km/h = 2 hours

Therefore, it will take the ship 2 hours to catch up with the motorboat.

Please note that the calculations assume constant speeds for both the motorboat and the ship throughout the journey.