Determine the probability the trains meet at the station

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Train X and Y arrive at a station randomly between 8 am and 8:20 am, stopping for 4 minutes, and their arrivals are independent. The probability of the trains meeting at the station depends on whether one train arrives within 4 minutes of the other. Clarifications are needed regarding the specific probabilities being asked, particularly for Train X and the conditions under which they meet. The original questions were perceived as unclear, leading to confusion among participants. Seeking further clarification from the lecturer is recommended for better understanding.
hamumej
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Train X and Y arrive at a station at random between 8 am to 8.20 am trains stop 4 min assuming that the trains arrive independently.
1. Determine the probability the train X.
2. Determine the probability the train meet at the station.
3. Assuming that the trains meet; Determine the probability the trains arrive.
:confused: :confused: :confused: :cry:
 
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Please rewrite that so as to make sense. Also, what have you tried?
 
hamumej said:
Train X and Y arrive at a station at random between 8 am to 8.20 am trains stop 4 min assuming that the trains arrive independently.
1. Determine the probability the train X.
Determine the probability that the train does what? Arrive at the station at a specific time?

2. Determine the probability the train meet at the station.
In other words that one arrives within four minutes of the other.

3. Assuming that the trains meet; Determine the probability the trains arrive.
?? You are given that the trains arrive! That probability is 1. That the trains arrive when?
:confused: :confused: :confused: :cry:[/QUOTE]
Yes, you are. Take a deep breath, go back and read the questions again. I guarantee they are not what you wrote!
 
would like to help but i don't understand your question:confused:
 
Thank you for any reply. I got 5 question from my class. I also didn't get this question. I will go back to ask my lecturer about the question again.
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks
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