Question

Собственая скорость лодки 15 км ч. скорость течения реки 3 км ч. сколько времени понадобится, чтобы на этой лодке проплыть 36 км по реке и вернутся обратнр

Answer 1

1) 15+3=18(км/ч) скорость лодки по течению
2) 15-3=15(км/ч) скорость лодки против течения
3) 36:18=2(часа) время по течению
4) 36:12=3(часа) время против течения
5)3+2=5(часов)

Answer 2

Calculating Time to Travel Upstream and Downstream

To calculate the time it will take to travel 36 km upstream and then return downstream, we can use the formula:

Time = Distance / Relative Speed

Where the relative speed is the difference between the boat's speed and the river's speed for upstream travel and the sum of the boat's speed and the river's speed for downstream travel.

Upstream Travel

The boat's speed is 15 km/h, and the river's speed is 3 km/h. Therefore, the relative speed for upstream travel is 15 km/h - 3 km/h = 12 km/h.

Using the formula, the time to travel 36 km upstream is:

Time = 36 km / 12 km/h = 3 hours

Downstream Travel

For downstream travel, the relative speed is 15 km/h + 3 km/h = 18 km/h.

Using the formula, the time to travel 36 km downstream is:

Time = 36 km / 18 km/h = 2 hours

Total Time for Round Trip

To find the total time for the round trip, we add the time for upstream travel and downstream travel:

Total Time = Upstream Time + Downstream Time = 3 hours + 2 hours = 5 hours

Therefore, it will take 5 hours to travel 36 km up the river and return downstream on this boat.