Question

Собственная скорость теплохода равна 20 1/2 км / ч , скорость течения реки 1 7/8 км / ч . Найдите скорость теплохода по течению реки и его скорость по течению

Answer 1

20 1/2+1 7/8=20 4/8+1 7/8=21 11/8=22 3/8км/ч скорость по течению
20 1/2-1 7/8=20 4/8-1 7/8=19 12/8-1 7/8=18 5/8км/ч скорость против течения

Answer 2

Calculation of the Speed of the Boat and River Current

To find the speed of the boat relative to the river current and the speed of the river current, we can use the following information:

- The speed of the boat is given as 20 1/2 km/h. - The speed of the river current is given as 1 7/8 km/h.

To calculate the speed of the boat relative to the river current, we subtract the speed of the river current from the speed of the boat:

Speed of the boat relative to the river current = Speed of the boat - Speed of the river current

Let's calculate this:

Speed of the boat = 20 1/2 km/h = 20.5 km/h Speed of the river current = 1 7/8 km/h = 1.875 km/h

Speed of the boat relative to the river current = 20.5 km/h - 1.875 km/h

To subtract the fractions, we need to find a common denominator. The common denominator for 2 and 8 is 8. Therefore, we can rewrite 20.5 km/h as 20 4/8 km/h.

Speed of the boat relative to the river current = 20 4/8 km/h - 1 7/8 km/h

Now, we can subtract the fractions:

Speed of the boat relative to the river current = (20 * 8 + 4) / 8 km/h - (1 * 8 + 7) / 8 km/h

Speed of the boat relative to the river current = (164/8) km/h - (15/8) km/h

Speed of the boat relative to the river current = (164 - 15) / 8 km/h

Speed of the boat relative to the river current = 149/8 km/h

Simplifying the fraction, we get:

Speed of the boat relative to the river current = 18 5/8 km/h

Therefore, the speed of the boat relative to the river current is 18 5/8 km/h.

To calculate the speed of the river current, we subtract the speed of the boat relative to the river current from the speed of the boat:

Speed of the river current = Speed of the boat - Speed of the boat relative to the river current

Speed of the boat = 20 1/2 km/h = 20.5 km/h Speed of the boat relative to the river current = 18 5/8 km/h

Speed of the river current = 20.5 km/h - 18 5/8 km/h

To subtract the fractions, we need to find a common denominator. The common denominator for 2 and 8 is 8. Therefore, we can rewrite 20.5 km/h as 20 4/8 km/h.

Speed of the river current = 20 4/8 km/h - 18 5/8 km/h

Now, we can subtract the fractions:

Speed of the river current = (20 * 8 + 4) / 8 km/h - (18 * 8 + 5) / 8 km/h

Speed of the river current = (164/8) km/h - (149/8) km/h

Speed of the river current = (164 - 149) / 8 km/h

Speed of the river current = 15/8 km/h

Therefore, the speed of the river current is 15/8 km/h.

To summarize: - The speed of the boat relative to the river current is 18 5/8 km/h. - The speed of the river current is 15/8 km/h.

Please note that these calculations are based on the given information and assumptions made.