A Pre-RMO question! -1
How many subsets of elements can be removed from the set { } such that the mean becomes ?
The answer is 5.
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1 solution
Mean of all the elements of the set is 6 . If we continue removing the subsets ( 1 , 1 1 ) , ( 2 , 1 0 ) , ( 3 , 9 ) , ( 4 , 8 ) , ( 5 , 7 ) , the mean of the elements of the remaining set always remains 6 . Hence the required answer is 5 .