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There are 3 piles of identical red, blue, and green balls, where each pile contains at least 10 balls. In how many ways can 10 balls be selected?

(a) No restriction
(b) At most one red ball is selected
(c) At least one red ball is selected
(d) Exactly one red ball is selected

1 Answer

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Final answer:

The student's question relates to combinatorics and involves calculating the number of ways to select 10 balls from 3 piles with different color balls under varying conditions. A combination formula with repetitions is typically used to solve this type of problem, and conditions such as 'at most', 'at least', and 'exactly' one red ball affect how the combinations are counted.

Step-by-step explanation:

The student is asking about the number of ways to select balls from piles with different color balls, under various conditions. This is a combinatorics problem that can be approached using combinations and permutations.

(a) With no restriction, we can simply choose any 10 balls from the total since each pile contains at least 10 balls. The number of ways can be calculated by using a combination formula with repetitions.

(b) If at most one red ball is selected, we must calculate the ways to select one red ball and the rest from the other colors, plus the ways to select all 10 balls without any red balls.

(c) For at least one red ball to be selected, we can find the total number of ways to select 10 balls with no restriction and subtract the number of ways to select 10 balls with no red balls.

(d) When exactly one red ball is selected, we select one red ball and then choose the remaining nine balls from the blue and green piles.

Each of these scenarios would be solved using the appropriate combinations and considering the piles as separate entities where balls can be selected.

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