Question

Лодка плывет по течению реки со скоростью шесть целых четыре пятых км/ч.Скорость течения реки равна две целых одна четвертая.Найдите скорость лодки против течения.

Answer 1

6 4/5-2 1/4=6 16/20- 2 5/20=4 11/20(км/ч)-скорость движения против течения

Answer 2

Calculation of the Boat's Speed Against the Current

To find the speed of the boat against the current, we need to subtract the speed of the current from the speed of the boat when it is moving with the current.

Given information: - Speed of the boat with the current: 6 4/5 km/h - Speed of the current: 2 1/4 km/h

To calculate the speed of the boat against the current, we subtract the speed of the current from the speed of the boat with the current:

Speed of the boat against the current = Speed of the boat with the current - Speed of the current

Let's perform the calculation:

Speed of the boat against the current = 6 4/5 km/h - 2 1/4 km/h

To subtract fractions, we need to find a common denominator. In this case, the common denominator is 20.

Converting the fractions to have a common denominator:

Speed of the boat against the current = (6 * 20 + 4) / 5 km/h - (2 * 20 + 1) / 4 km/h

Simplifying the fractions:

Speed of the boat against the current = (120 + 4) / 5 km/h - (40 + 1) / 4 km/h

Speed of the boat against the current = 124 / 5 km/h - 41 / 4 km/h

To subtract fractions, we need to have a common denominator. In this case, the common denominator is 20.

Converting the fractions to have a common denominator:

Speed of the boat against the current = (124 * 4) / (5 * 4) km/h - (41 * 5) / (4 * 5) km/h

Simplifying the fractions:

Speed of the boat against the current = 496 / 20 km/h - 205 / 20 km/h

Subtracting the fractions:

Speed of the boat against the current = (496 - 205) / 20 km/h

Calculating the numerator:

Speed of the boat against the current = 291 / 20 km/h

Therefore, the speed of the boat against the current is 14 11/20 km/h.