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From the context, the marbles differ by their colors only (since the opposite is not stated).
Let R be the number of red marbles among 5 selected marbles.
Then the number of different cases (the number "in how many ways can this be done") is equal to the number of solution to this inequality
1 <= R <= 5.
The number of solution is 5.
Therefore, the ANSWER to the problem's question is 5.