Question

Катер проплыл по теч реки за 1,4 часа а против течения за 2,2ч.Найдите чудо катера в стоячей воде если скор течения 1,8 км/ч

Answer 1

(х+1,8)×1,4
(х-1,8)×2,2
1,4х+1,4×1,8=2,2х-2,2×1,8
2,2×х-1,4х=2,2×1,8+1,4×1,8
х=8,1км ч

Answer 2

Calculation of the Boat's Speed in Still Water

To find the speed of the boat in still water, we can use the formula:

Boat's speed in still water = (Speed downstream + Speed upstream) / 2

Given that the boat took 1.4 hours to travel downstream and 2.2 hours to travel upstream, we can calculate the speed of the boat in still water.

Let's denote the speed of the boat in still water as x and the speed of the current as y.

The boat's speed downstream can be calculated as:

Speed downstream = (Distance downstream) / (Time downstream) = (x + y) / 1.4

The boat's speed upstream can be calculated as:

Speed upstream = (Distance upstream) / (Time upstream) = (x - y) / 2.2

Using the given information, we can set up the following equations:

(x + y) / 1.4 = (x - y) / 2.2

To solve this equation, we can cross-multiply and simplify:

(x + y) * 2.2 = (x - y) * 1.4

Simplifying further:

2.2x + 2.2y = 1.4x - 1.4y

0.8x = 3.6y

Now, we can solve for x in terms of y:

x = (3.6y) / 0.8 = 4.5y

Therefore, the speed of the boat in still water is 4.5 times the speed of the current.

Calculation of the Current's Speed

Given that the speed of the current is 1.8 km/h, we can substitute this value into the equation we derived earlier to find the speed of the boat in still water.

x = 4.5y

x = 4.5 * 1.8

x = 8.1 km/h

Therefore, the speed of the boat in still water is 8.1 km/h.

Conclusion

The boat's speed in still water is 8.1 km/h, and the speed of the current is 1.8 km/h.