Question

а)скорость товарного поезда на 40км/ч меньше скорости пассажирского.товарный поезд за 7 ч проходит такой же путь,как пассажирский за 4,2 ч.Найдите скорость товарного поезда. б) найдите корень уравнения |-0,57|=|-3,8|*|y|

Answer 1

1) Скорость товарного Х- 40

Скорость пассажирского Х 

7(X-40) = 4.2Х

7Х - 280 = 4.2X

2.8X = 280

X = 100 (км\час) - скорость пассажирского

100 - 40 = 60 

ОТВЕТ: скорость товарного поезда 60 км\час

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2) | - 0.57| = |-3.8| *|Y|

- 0,57 = - 3.8Y

Y = 0.15

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0.57 = 3.8 *- Y

Y = - 0.15

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Answer 2

а) Let's solve the problem step by step.

Given: - The speed of the goods train is 40 km/h less than the speed of the passenger train. - The goods train takes 7 hours to travel the same distance as the passenger train in 4.2 hours.

We need to find the speed of the goods train.

Let's assume the speed of the passenger train as "x" km/h. Then the speed of the goods train will be "x - 40" km/h.

We can use the formula: Speed = Distance / Time.

For the passenger train: Distance = x * 4.2 (since it takes 4.2 hours to travel the distance) Speed = x km/h Time = 4.2 hours

For the goods train: Distance = (x - 40) * 7 (since it takes 7 hours to travel the same distance) Speed = (x - 40) km/h Time = 7 hours

Setting up the equation: x * 4.2 = (x - 40) * 7

Simplifying the equation: 4.2x = 7x - 280 -2.8x = -280 x = -280 / -2.8 x = 100

Therefore, the speed of the passenger train is 100 km/h.

To find the speed of the goods train: Speed of goods train = x - 40 = 100 - 40 = 60 km/h

So, the speed of the goods train is 60 km/h.

б) Now let's solve the equation | -0.57 | = | -3.8 | * | y |.

|-0.57| = |-3.8| * |y|

Taking the absolute value of -0.57 gives us 0.57, and taking the absolute value of -3.8 gives us 3.8.

0.57 = 3.8 * |y|

To solve for |y|, we can divide both sides of the equation by 3.8:

0.57 / 3.8 = |y|

0.15 = |y|

Therefore, the value of |y| is 0.15.