Combinations for word parallelogram

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Homework Help Overview

The discussion revolves around determining the number of ways to select four letters from the word "parallelogram," which contains repeating letters. Participants are exploring how to account for these repetitions in their calculations.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants are considering combinations and questioning whether to treat repeated letters as distinct or identical. There is confusion regarding the correct combinatorial approach, with some suggesting the use of combinations like 8C4 and others questioning the interpretation of the problem.

Discussion Status

The discussion is ongoing, with participants raising various interpretations of the problem and the implications of letter repetition. Some guidance has been offered regarding the ambiguity of the original question, but no consensus has been reached.

Contextual Notes

There is uncertainty about whether the selection of four letters must include different letters or if repetitions are allowed. The original question's wording is noted as potentially vague, contributing to the confusion.

haribol
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How many ways can you select four letters out of the word parallelogram ?

The answer on the book is 150. For me I am stuck at using 8C4 and it seems to be the logical way. The reason I chose 8 is because some letters are repeating. So how can they have 150?
 
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4 letters or 4 different letters?

cookiemonster
 
It just says four letters, not four different letters
 
You can't just remove those letters since you can have a combo of aaap and aapl and aplo. Eliminating those letters will eliminate a lot of your combinations.
 
I see, but 13C4 is quite big relative to 150 and I see no way how its 150
 
Well, one thing is that para and para, while different selections, constitute the same 4 letters, I suppose, so shouldn't both be counted. The question as stated is vague on this point!
 
The original question from the text is as follows:

"Determine the number of ways of selecting, without regard to order, from the word parallelogram"
 

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