Question

2. Реши задачу: Слон пробежал 90 км со скоростью 45 км/ч. Жираф потратил на этот путь на 4 часа больше. С какой скоростью бежал жираф?​

Answer 1

Ответ:

90:45=2часа

2+4=6часов

90:6=15км\час

Answer 2

90:45=2ч
2+4=6ч
90:6=15км/ч

Answer 3

Problem Analysis

To solve this problem, we need to find the speed at which the giraffe ran. We are given that the elephant ran a distance of 90 km at a speed of 45 km/h. Additionally, we know that the giraffe took 4 hours longer to cover the same distance. We need to determine the speed at which the giraffe ran.

Solution

Let's assume the speed of the giraffe is x km/h. We can set up the following equation based on the information given:

Distance = Speed × Time

For the elephant: Distance = 90 km Speed = 45 km/h Time = unknown

For the giraffe: Distance = 90 km Speed = x km/h Time = unknown

Since the distance is the same for both animals, we can equate the two equations:

45 × Time of the elephant = x × (Time of the elephant + 4)

Simplifying the equation, we get:

45 × Time = x × (Time + 4)

Let's solve this equation to find the value of x.

Calculation

To solve the equation, we can expand it and rearrange the terms:

45 × Time = x × Time + 4x

Subtracting x × Time from both sides:

45 × Time - x × Time = 4x

Factoring out Time:

Time × (45 - x) = 4x

Dividing both sides by (45 - x):

Time = (4x) / (45 - x)

Now we have an equation for the time taken by the elephant. We can substitute this value into the equation for the giraffe's time to find the value of x.

Time of the giraffe = Time of the elephant + 4

Substituting the value of Time:

(4x) / (45 - x) + 4 = Time of the elephant + 4

Simplifying the equation:

(4x) / (45 - x) = Time of the elephant

Substituting the value of Time of the elephant:

(4x) / (45 - x) = (4x) / (45 - x)

Now we have an equation for the time taken by the giraffe. We can solve this equation to find the value of x.

Solution

To find the value of x, we can cross-multiply and solve for x:

(4x) × (45 - x) = (4x) × (45 - x)

Expanding the equation:

180x - 4x^2 = 180x - 4x^2

Simplifying the equation:

180x - 4x^2 - 180x + 4x^2 = 0

Combining like terms:

0 = 0

Since the equation simplifies to 0 = 0, this means that any value of x will satisfy the equation. Therefore, the speed at which the giraffe ran can be any value.

Answer

The speed at which the giraffe ran can be any value.