Thread: A difficult problem, help please!

Hi,

I'm struggling with a difficult problem, so I asking for your help.

This is it: A football fan wants to collect a set of 132 trading cards. Therefore he buys 2 packs/day with 1 card/pack. The chance is uniform, p=1/132. How many days does it take to collect the full set?

Normally, i have to use the program R to deal with this problem, but if you don't know how to begin, it's hard to program it. (comma is for decimal separation)

This is what i think i should do:
Give the cards a number from x=0 to x=131.
Then I calculate how many packs on average i need to buy. Thus y= 132/(132-x)

Then i sum up the result for each card x --> Σ(132/(132-x)) = 721,2217
This should then be divided by 2 packs per day, thus 360,6108 days.

Now i'm stuck because these results doesn't seem realistic to me. Is this calculation correct or is it wrong?

I've read the "coupon collector problem" on wiki, but i don't quite understand the explanation of it.

Could you help me, please?

Originally Posted by Leslon

Hi,

I'm struggling with a difficult problem, so I asking for your help.

This is it: A football fan wants to collect a set of 132 trading cards. Therefore he buys 2 packs/day with 1 card/pack. The chance is uniform, p=1/132. How many days does it take to collect the full set?

Normally, i have to use the program R to deal with this problem, but if you don't know how to begin, it's hard to program it.

This is what i think i should do:
Give the cards a number from 0 to 131.
Then I calculate how

Hi Leslon,

This is the classic "coupon collector's problem". You can find an analysis here: Coupon collector's problem - Wikipedia, the free encyclopedia

Thank you for giving me the link to wiki. But i don't quite understand it yet. I completed my earlier post with a calculation i made. Could you tell me i'm right or wrong?

Hi Leson,

Your result of 360.6 days agrees with the formula in the Wikipedia article.