Question

Помогите срочноо С решением От пункта A до пункта B машина проехала 60км/ч, а обратно 80км/ч. Чему равно расстояние между пунктами, если на весь путь он потратил 7 часов?

Answer 1

х  км - расстояние

х/60 + х/80=7    (общ.знаменатель 240)

4х+3х=7*240

7х=1680

х=1680:7

х=240(км) - расстояние между А и В

Answer 2

Х/60 + х/80 = 7
4х + 3х = 7 × 240
7х = 1680
х = 240 (км)
Ответ: S = 240 км.

Answer 3

Problem Analysis

We are given that a car traveled from point A to point B at a speed of 60 km/h and returned from point B to point A at a speed of 80 km/h. The total time taken for the entire journey was 7 hours. We need to find the distance between point A and point B.

Solution

Let's assume the distance between point A and point B is d km.

To find the distance, we can use the formula: distance = speed × time.

We know that the car traveled from point A to point B at a speed of 60 km/h. So, the time taken for this part of the journey can be calculated as d/60 hours.

Similarly, the car traveled from point B to point A at a speed of 80 km/h. So, the time taken for this part of the journey can be calculated as d/80 hours.

According to the problem, the total time taken for the entire journey is 7 hours. So, we can write the equation:

d/60 + d/80 = 7

To solve this equation, we can multiply both sides by the least common multiple (LCM) of 60 and 80, which is 240:

4d + 3d = 7 × 240

Simplifying the equation:

7d = 1680

Dividing both sides by 7:

d = 240

Therefore, the distance between point A and point B is 240 km.

Answer

The distance between point A and point B is 240 km.

Verification

Let's verify the answer using the given information.

The car traveled from point A to point B at a speed of 60 km/h. So, the time taken for this part of the journey is 240/60 = 4 hours.

The car traveled from point B to point A at a speed of 80 km/h. So, the time taken for this part of the journey is 240/80 = 3 hours.

The total time taken for the entire journey is 4 hours + 3 hours = 7 hours, which matches the given information.

Therefore, the answer is verified.