Question

геологи проехали 195 км. 3 часа они плыли на моторной лодке и 5 часов на пароходе. Найдите скорость моторной лодки, если она в два раза меньше скорости парохода. Помогите плз.

Answer 1

1) х км/ч - скорость моторно лодки

2) 2х км/ч - скорость теплохода.
3) Получаем уравнение:
3х+5*2х=195
3х+10х=195
13х=195
х=195:13
х= 15(км/ч) - скорость моторной лодки

Answer 2

Problem Analysis

To find the speed of the motorboat, we need to use the given information about the distance traveled and the time taken on both the motorboat and the steamboat. We are also given that the speed of the motorboat is half the speed of the steamboat.

Solution

Let's denote the speed of the motorboat as x km/h and the speed of the steamboat as 2x km/h (since the speed of the motorboat is half the speed of the steamboat).

We can calculate the time taken on the motorboat using the formula: time = distance / speed.

The distance traveled on the motorboat is 195 km, and the time taken on the motorboat is 3 hours. Therefore, we have:

3 = 195 / x Similarly, we can calculate the time taken on the steamboat using the same formula:

The distance traveled on the steamboat is also 195 km, and the time taken on the steamboat is 5 hours. Therefore, we have:

5 = 195 / (2x) Now, we can solve these two equations to find the value of x, which represents the speed of the motorboat.

Calculation

Let's solve the equations:

From equation 1: 3 = 195 / x, we can multiply both sides by x to eliminate the denominator:

3x = 195

From equation 2: 5 = 195 / (2x), we can multiply both sides by 2x to eliminate the denominator:

10x = 195

Now, we can solve for x by dividing both sides of the equation by 3:

x = 65

Answer

The speed of the motorboat is 65 km/h.

Explanation

According to the given information, the motorboat traveled a distance of 195 km in 3 hours, while the steamboat traveled the same distance in 5 hours. Since the speed of the motorboat is half the speed of the steamboat, we can set up equations to represent the time taken on each boat. By solving these equations, we find that the speed of the motorboat is 65 km/h.