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Question Number 104876 by mathocean1 last updated on 24/Jul/20

A b a l l o t b o x c o n t a i n s 7 b a l l s (3 a r e

b l a c k) . w e d r a w s u c c e s s i v e l y a n d

r e p u t i n g (i n s i d e) 5 b a l l s .

W h a t i s t h e n u m b e r o f p o s s i b i l i t i e s

t o h a v e o n e b l a c k b a l l ?