Question

С одного цветка одновременно вылетели в противоположные стороны две стрекозы.Через 0,08 ч между ними было 4,4 км.Скорость одной стрекозы 28,8 км/ч.Найдите скорость полёта другой стрекозы.

Answer 1

1) 28,8*0,08=2,304 (км) 
2) 4,4 -2,304=2,096 (км) 
3) 2,096:0,08=26,2 (км/ч) 
Ответ: 26,2 км/ч 

Answer 2

Problem Analysis

We are given that two dragonflies flew in opposite directions from the same flower. The distance between them after 0.08 hours was 4.4 km. We also know that the speed of one dragonfly is 28.8 km/h. We need to find the speed of the other dragonfly.

Solution

Let's assume the speed of the other dragonfly is x km/h.

We can use the formula: distance = speed × time.

For the first dragonfly: - Speed = 28.8 km/h - Time = 0.08 hours

Using the formula, we can calculate the distance traveled by the first dragonfly: distance1 = speed1 × time1

For the second dragonfly: - Speed = x km/h - Time = 0.08 hours

Using the formula, we can calculate the distance traveled by the second dragonfly: distance2 = speed2 × time2

Since the two dragonflies flew in opposite directions, the sum of their distances should be equal to the total distance between them: distance1 + distance2 = 4.4 km

Substituting the values, we get: (28.8 × 0.08) + (x × 0.08) = 4.4

Simplifying the equation, we have: 2.304 + 0.08x = 4.4

Now, let's solve for x to find the speed of the second dragonfly.

Calculation

2.304 + 0.08x = 4.4

Subtracting 2.304 from both sides: 0.08x = 2.096

Dividing both sides by 0.08: x = 26.2

Answer

The speed of the second dragonfly is 26.2 km/h.

Verification

To verify our answer, let's substitute the value of x into the equation and check if the distances add up to 4.4 km.

For the first dragonfly: distance1 = speed1 × time1 = 28.8 × 0.08 = 2.304 km

For the second dragonfly: distance2 = speed2 × time2 = 26.2 × 0.08 = 2.096 km

Adding the distances: distance1 + distance2 = 2.304 + 2.096 = 4.4 km

The distances add up to 4.4 km, which confirms that our answer is correct.

Therefore, the speed of the second dragonfly is 26.2 km/h.