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femz

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Kindly help with the following questions

 

1. Suppose that we have to distribute n indistinguishable apples between k dis- tinguishable baskets. How many ways can we do that? Please explain your answer. Provide solution to the question assuming that there are more apples than baskets and no basket is empty.

 

2. Suppose a social network contains a number of people, each of whom has one of two “opinions” (e.g. a preference for Mac versus PC). Each person is connected with a set of “friends”, some of the other people in the network. You can choose any person in the network and let them see the opinions of their friends, and if most of the friends have the same opinion, them the chosen person will change their opinion to the one shared by the majority of their friends. If there’s an equal split, you can choose their opinion. Assuming the network is connected, can we always find a sequence of people so as to ensure that they all end up with the same opinion?


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Kindly help with the following questions

 

1. Suppose that we have to distribute n indistinguishable apples between k dis- tinguishable baskets. How many ways can we do that? Please explain your answer. Provide solution to the question assuming that there are more apples than baskets and no basket is empty.

 

 

2. Suppose a social network contains a number of people, each of whom has one of two “opinions” (e.g. a preference for Mac versus PC). Each person is connected with a set of “friends”, some of the other people in the network. You can choose any person in the network and let them see the opinions of their friends, and if most of the friends have the same opinion, them the chosen person will change their opinion to the one shared by the majority of their friends. If there’s an equal split, you can choose their opinion. Assuming the network is connected, can we always find a sequence of people so as to ensure that they all end up with the same opinion?

 

 

 

 

Since no basket can be empty, the first thing you want to do is put one apple in each basket. That leaves n-k apples to be distributed among k baskets. You could put all n-k apples in any one of the k baskets- there are k ways to do that. You could put n-k-1 apples in one basket, one apple in another basket. There are k choices for the first basket, k- 1 choices for the second basket so there are k(k-1) ways to do that. Continue.

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Since no basket can be empty, the first thing you want to do is put one apple in each basket. That leaves n-k apples to be distributed among k baskets. You could put all n-k apples in any one of the k baskets- there are k ways to do that. You could put n-k-1 apples in one basket, one apple in another basket. There are k choices for the first basket, k- 1 choices for the second basket so there are k(k-1) ways to do that. Continue.

Alternatively, he could try doing his homework a little earlier and, when he asks for help, show how far he has got up until that point and why he thinks he has got stuck.

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  • 4 weeks later...
  • 10 months later...

Hi,

can somebody please help me with these two  questions?

 

1)Suppose a social network contains a number of people, each of whom has one of two “opinions” (e.g. a preference for Mac versus PC). Each person is connected with a set of “friends”, some of the other people in the network. You can choose any person in the network and let them see the opinions of their friends, and if most of the friends have the same opinion, then the chosen person will change their opinion to the one shared by the majority of their friends. If there’s an equal split, you can choose their opinion. Assuming the network is connected, can we always find a sequence of people so as to ensure that they all end up with the same opinion?

 

2)Two ants walk on a line in a random fashion. They begin 10cm apart. At each time step, each ant has a probability of 1/2 to move 1cm to the left, and probability 1/2 to move 1cm to the right. What is the probability that after 7 time steps, the ants have met one another (i.e., passed through the same point)?

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femz and anum,

It is an entirely reasonable policy for the forum to provide help but not answers.  Providing help can take time; therefore, waiting until it becomes "urgent" is not a good strategy.

femz, "thanks guys, i actually don't know it atall. so,i waited to get more answer so i can compare" is basically stating that you want us to provide you with multiple answers to a question that you have not thought about in the slightest.

anum,  Please don't post the same question in a different thread.

 

 

Edited by BabcockHall
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