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Andreyy89
3 years ago
10

A train travels 110 km in the same time that a plane covers 385 km. If the speed of the plane is 20 km per hr less than 4 times

the speed of the train, find the speeds.
Trains speed: __ km per hr
Plane's speed — km per hr
Mathematics
2 answers:
Ierofanga [76]3 years ago
8 0

Answer:

Two identical trains, Train A and Train B, are traveling along parallel rails.

The speed of Train A is 88 km/hr, and the speed of Train B is 96 km/hr. Based on this information, which of the following statements is true?

A.

Train B has more kinetic energy than Train A.

B.

Train A has more kinetic energy than Train B.

C.

The trains have the same kinetic energy.

D.

Neither train has any kinetic energy.

Step-by-step explanation:

slamgirl [31]3 years ago
4 0

Answer:

  • train: 40 kph
  • plane: 140 kph

Step-by-step explanation:

Let t represent the speed of the train in km/h. Then 4t-20 is the speed of the plane. Travel times are the same, so we can use the formula ...

  time = distance/speed

and equate the travel times.

  110/t = 385/(4t-20)

Cross multiplying gives ...

  110(4t -20) = 385t

  440t -2200 = 385t . . . . . eliminate parentheses

  55t -2200 = 0 . . . . . . . . . subtract 385t

  t -40 = 0 . . . . . . . . . divide by 55

  t = 40 . . . . . . . . . . . add 40; train's speed is 40 kph

  4t -20 = 140 . . . . . . find plane's speed; 140 kph

The train's speed is 40 km/h; the plane's speed is 140 km/h.

_____

<em>Check</em>

Train's travel time = 110 km/(40 km/h) = 2.75 h.

Plane's travel time = 385 km/(140 km/h) = 2.75 h.

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The level of nitrogen oxides (NOX) in the exhaust after 50,000 miles or fewer of driving of cars of a particular model varies No
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Answer:

For a level of 0.0174 or more of nitrogen oxide, the probability of fleet is 0.01.              

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 0.02 g/mi

Standard Deviation, σ = 0.01 g/mi

Sample size, n = 81

We are given that the distribution of  level of nitrogen oxides is a bell shaped distribution that is a normal distribution.

Standard error due to sampling:

=\dfrac{\sigma}{\sqrt{n}} = \dfrac{0.01}{\sqrt{81}} = 0.0011

Formula:

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We have to find the value of x such that the probability is 0.01

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P( X > x) = P( z > \displaystyle\frac{x - 0.02}{0.0011})=0.01  

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Answer:

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Step-by-step explanation:

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2. 2nd Possibility

First Z, then Y and then X on the line or line segment

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