Question

Автомобиль проехал из пункта A в пункт B со скоростью 70 км/ч. На обратном пути он уменьшил скорость на 10км/ч и затратил на дорогу на 45 минут больше. Найдите расстояние между A и B.

Answer 1

1)Даны два числа x и y известно x-y=5 и (2/3)*x=0.8*y .Тогда x=5+y или x=1.2*y следовательно 1.2*y=5+y => y=25 а x=30 !! 

2) Дана скорость v1=70 v2=60 .Пусть t время пути а S растояние от A до B .S=v1*t или S=v2*(t+3/4) так как 60 мин в часе а 45 мин это 3/4.Получим v1*t=v2*(t+3/4) => 70*t=60t+45 t=4.5 часа или 270мин. S=v1*t S=70*4.5=315км

как в школе решим!!!
спасибо говорим!!!) 

Answer 2

х час - время на прямой путь

45 мин = 0,75 часа

х+0,75 час - время на обратный путь

70х=60(х+0,75)

70х=60х+45

10х=45

х=4,5 (часа) - время на прямой путь

70*4,5=315 (км) - расстояние между А и В                          

                                                                                                                                                                                             

Answer 3

Calculation of Distance between Points A and B

To find the distance between points A and B, we need to consider the information provided:

- The car traveled from point A to point B at a speed of 70 km/h. - On the return trip, the car reduced its speed by 10 km/h. - The return trip took 45 minutes longer than the initial trip.

To calculate the distance between points A and B, we can use the formula:

Distance = Speed × Time

Let's break down the problem step by step:

1. Calculate the time taken for the initial trip from point A to point B.

- Speed = 70 km/h - Time = Distance / Speed

2. Calculate the time taken for the return trip from point B to point A.

- Speed = 70 km/h - 10 km/h (reduced speed) - Time = Distance / Speed + 45 minutes

3. Equate the time taken for the initial trip and the return trip to find the distance.

Now let's calculate the distance using the given information.

Calculation Steps:

1. Calculate the time taken for the initial trip from point A to point B:

- Speed = 70 km/h - Time = Distance / Speed

2. Calculate the time taken for the return trip from point B to point A:

- Speed = 70 km/h - 10 km/h (reduced speed) - Time = Distance / Speed + 45 minutes

3. Equate the time taken for the initial trip and the return trip to find the distance:

- Time (initial trip) = Time (return trip) - Distance / 70 = Distance / (70 - 10) + 45 minutes

Now let's solve the equation to find the distance.

Solution:

1. Calculate the time taken for the initial trip from point A to point B:

- Speed = 70 km/h - Time = Distance / Speed

2. Calculate the time taken for the return trip from point B to point A:

- Speed = 70 km/h - 10 km/h = 60 km/h - Time = Distance / Speed + 45 minutes

3. Equate the time taken for the initial trip and the return trip to find the distance:

- Distance / 70 = Distance / 60 + 45 minutes

To solve this equation, we need to convert the 45 minutes to hours:

- 45 minutes = 45 / 60 = 0.75 hours

Now let's substitute the values into the equation:

- Distance / 70 = Distance / 60 + 0.75

To simplify the equation, we can multiply both sides by the common denominator of 420:

- 420 * (Distance / 70) = 420 * (Distance / 60 + 0.75)

Simplifying further:

- 6 * Distance = 7 * Distance + 315

Moving all the terms involving Distance to one side:

- 7 * Distance - 6 * Distance = 315

Simplifying:

- Distance = 315

Therefore, the distance between points A and B is 315 kilometers.

Please note that the calculation assumes a constant speed throughout the journey and does not take into account any other factors that may affect the actual distance traveled.