Do numbers make you numb?
Probability
Level
3
If the number of 9 digit numbers that have 2 between 1 and 3, 5 between 4 and 6, and 8 between 7 and 9 are given by 9!/n, then find n.
36
3!
(3!)^3
3^3
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1 solution
These are independent constraints allowing for example 123 and 321 out of six permutations of the positioning of 1 , 2 and 3 in the 9 digit number. Hence divide 9! by 3 three times.