MATHCOUNTS 2026 State Sprint Round (Problem 20)
How many distinct arrangements of the letters in the word PROBABILITY contain the sub-arrangement PRO, whose letters must appear consecutively and in that order anywhere in the arrangement?
Put a box around PRO.
There are objects (consider the box as one object).
Since there are two B's and two I's, divide byTherefore,
Since there are two B's and two I's, divide byTherefore,
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