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Divide 3 groups first.! [% q6 r& M! C* d3 e5 D
i.e. 4 x 4 x 4.! D% @4 n- Y# N% }  |
Weight any 2 groups [1st]' Z( @$ F- d. O( m+ N
then you will know the heavier ball in which group.
8 \, O1 }* I& `; u8 h0 [) S5.39.217.76Weight any 2 balls in that group [2nd]
8 H% r/ }5 }& l2 a' T% v) ~: Xthen you will know the heavier ball in which 2 balls." S+ O$ d* K$ G9 }* \
Repeat again in remainders [3rd]5.39.217.767 C6 ^) d9 m! y3 i
Got the heavier ball.