Question

Решите задачу дикая утка от Южного моря до Северного моря летит 7 дней дикий гусь от северного моря до Южного моря летит 9 дней через сколько дней они встретятся если вылететят одновременно

Answer 1

1)1:7=1/7(часть пути)-пролетит утка за 1 день
2)1/9=1/9(часть пути)-пролетит гусь за 1 день
3)1/7+1/9=9/63+7/63=16/63(часть/пути)-скорость сближения за 1 день
4)1:16/63=1/1*63/16=3 целых 15/16
Ответ: утка и гусь встретятся через 3 целых пятнадцать шестнадцатый или 3 целых 15/16

Answer 2

Problem Analysis

We are given that a wild duck flies from the South Sea to the North Sea in 7 days, while a wild goose flies from the North Sea to the South Sea in 9 days. We need to determine how many days it will take for them to meet if they start flying at the same time.

Solution

To solve this problem, we can use the concept of relative speed. The relative speed is the sum of the speeds of the two birds. Let's assume the speed of the wild duck is D and the speed of the wild goose is G.

Since the wild duck flies from the South Sea to the North Sea in 7 days, we can calculate its speed as the distance divided by the time: D = Distance / Time = 1 / 7.

Similarly, since the wild goose flies from the North Sea to the South Sea in 9 days, we can calculate its speed as: G = Distance / Time = 1 / 9.

To find the time it takes for them to meet, we can use the formula: Time = Distance / Relative Speed.

Since the distance covered by both birds is the same, we can substitute the distance with 1 in the formula. The relative speed is the sum of their speeds: Relative Speed = D + G.

Substituting the values, we get: Time = 1 / (D + G).

Let's calculate the time it takes for them to meet:

D = 1 / 7 (speed of the wild duck) G = 1 / 9 (speed of the wild goose)

Relative Speed = D + G = (1 / 7) + (1 / 9) Time = 1 / (D + G) = 1 / ((1 / 7) + (1 / 9))

Now, let's calculate the value of Time:

Time = 1 / ((1 / 7) + (1 / 9))

Using the formula for adding fractions, we can simplify the expression:

Time = 1 / ((9 + 7) / (7 * 9)) Time = 1 / (16 / 63) Time = 63 / 16

Therefore, it will take them 63 / 16 days to meet if they start flying at the same time.

Answer

If the wild duck and the wild goose start flying at the same time, they will meet in approximately 3.9375 days.