Question

Скорость теплохода 42 км/ч, а скорость течения реки 2 км/ч. 1) Сколько километров пройдет теплоход: а) за 3 часа, двигаясь по течению? б) за 2 часа, двигаясь против течения? в) за 1 часов, двигаясь по течению? г) за 1 часов, двигаясь против течения? 2) Сколько километров проплыл бы теплоход, двигаясь по озеру: а) за 3 часа? б) за 2,5 часа? в) за t часов? 3) Сколько километров проплыл бы теплоход, если он: а) сначала 2 часа плыл по озеру, а затем еще 2,5 часа плыл по реке по течению? б) сначала 3 часа плыл по реке против течения, а затем еще 2,5 часа плыл по озеру?​

Answer 1

Ответ:
1)44*3=132
2)40*2=80
3)44*1=44
4)40*1=40
1)42*3=126
2)42*2,5=105
3)42t

1)80+110=190
2)120+105=225

Answer 2

Question 1:

The speed of the boat is 42 km/h, and the speed of the river current is 2 km/h. We need to calculate the distance the boat will travel under different conditions.

a) To calculate the distance the boat will travel in 3 hours, moving with the current, we can use the formula: distance = speed * time. The boat's speed relative to the ground is the sum of its speed and the speed of the current. So the boat's speed with the current is 42 km/h + 2 km/h = 44 km/h. Therefore, the distance traveled in 3 hours is 44 km/h * 3 hours = 132 km.

b) To calculate the distance the boat will travel in 2 hours, moving against the current, we subtract the speed of the current from the boat's speed. So the boat's speed against the current is 42 km/h - 2 km/h = 40 km/h. Therefore, the distance traveled in 2 hours is 40 km/h * 2 hours = 80 km.

c) To calculate the distance the boat will travel in 1 hour, moving with the current, we use the same formula. The boat's speed with the current is 44 km/h. Therefore, the distance traveled in 1 hour is 44 km/h * 1 hour = 44 km.

d) To calculate the distance the boat will travel in 1 hour, moving against the current, we use the same formula. The boat's speed against the current is 40 km/h. Therefore, the distance traveled in 1 hour is 40 km/h * 1 hour = 40 km.

Question 2:

Now let's calculate the distance the boat would travel on a lake under different conditions.

a) To calculate the distance the boat will travel in 3 hours on the lake, we use the formula: distance = speed * time. The boat's speed on the lake is 42 km/h. Therefore, the distance traveled in 3 hours is 42 km/h * 3 hours = 126 km.

b) To calculate the distance the boat will travel in 2.5 hours on the lake, we use the same formula. The boat's speed on the lake is 42 km/h. Therefore, the distance traveled in 2.5 hours is 42 km/h * 2.5 hours = 105 km.

c) To calculate the distance the boat will travel in t hours on the lake, we use the same formula. The boat's speed on the lake is 42 km/h. Therefore, the distance traveled in t hours is 42 km/h * t hours = 42t km.

Question 3:

Let's calculate the distance the boat would travel if it first sailed on the lake for 2 hours and then sailed on the river with the current for 2.5 hours.

a) To calculate the distance the boat will travel if it first sails on the lake for 2 hours, we use the formula: distance = speed * time. The boat's speed on the lake is 42 km/h. Therefore, the distance traveled on the lake in 2 hours is 42 km/h * 2 hours = 84 km.

Then, the boat sails on the river with the current for 2.5 hours. The boat's speed with the current is 44 km/h. Therefore, the distance traveled on the river with the current in 2.5 hours is 44 km/h * 2.5 hours = 110 km.

The total distance traveled is the sum of the distances traveled on the lake and on the river: 84 km + 110 km = 194 km.

b) To calculate the distance the boat will travel if it first sails on the river against the current for 3 hours, we use the formula: distance = speed * time. The boat's speed against the current is 40 km/h. Therefore, the distance traveled on the river against the current in 3 hours is 40 km/h * 3 hours = 120 km.

Then, the boat sails on the lake for 2.5 hours. The boat's speed on the lake is 42 km/h. Therefore, the distance traveled on the lake in 2.5 hours is 42 km/h * 2.5 hours = 105 km.

The total distance traveled is the sum of the distances traveled on the river and on the lake: 120 km + 105 km = 225 km.

Note: The calculations assume a constant speed throughout the journey and do not take into account other factors such as changes in the current or the boat's acceleration and deceleration.