Posted by rob on Tuesday, January 26, 2010 at 10:40pm.
5 2's -- one way
4 2's 2 1's ---- number of ways = 6!/(4!2!) = 15
(e.g. 222211, 11222, 212122, etc )
3 2's 4 1's ---- number of ways = 7!/(4!3!) = 35
2 2's 6 1's ---- number of ways = 8!/(2!6!) = 28
1 2 8 1's ---- number of ways = 9!/(1!8!) = 9
all 1's ---- one way
total 1+15+35+28+9+1 = 89
Wow for grade 8!!!
89
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