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jmc

counting and probability senior

Problem

How many distinguishable ways are there to write as the sum of and where the order of the addends matters? For example, and are two different ways.
Solution
First, we find how many ways are there to write 9 as the sum of 1s, 2s and 4s, where the order of the addends does not matter. We find these cases: There are distinguishable orders for the first sum, for the second sum, for the third sum, for the fourth sum, for the fifth sum, for the sixth sum, for the seventh sum, for the eighth sum, and for the last sum. In total, there are distinguishable ways are there to write as the sum of and
Final answer
96