Elitmus
Exam
Numerical Ability
Averages
The average of 20 numbers is zero. Of them, How many of them may be greater than zero , at the most?
Options
1) 1
2) 20
3) 0
4) 19
Read Solution (Total 8)
-
- At the most 19 numbers can be greater than zero.
Since the 20th number can be equal to the negation of the sum of all 19 numbers .
consider n1, n2, n3....,n19 are all positive numbers and n20 = - (n1+ n2 + ...... n19)
then average = {(n1+ n2 + ..... n19) + (- (n1 + n2 +... n19)) }/ 20
= 0
- 9 years agoHelpfull: Yes(7) No(2)
- Ans : 3)0
Sol: let no is X1,X2,X3------------------------------------------X20;
average of those no is
=>(x1+x2+x3+----------------------------------+X20)/20=0
so X1+x2+x3+------------------------------------+x20=0
it possible only when at lest 1 digit should be negative and at most 19 digit should be negative
we put, put X1=19 and X2=X3=X4=-----------------------------------X20=-1
therefore (19-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1)/2-
=(19-19)/20
=0
- 9 years agoHelpfull: Yes(2) No(0)
- 4) 19 bcoz sum of 19 positive number must be counter balanced by negative number and that number could be equal to sum of 19 positive numbers
- 8 years agoHelpfull: Yes(2) No(0)
- atmost 19 because...
take any 19 elements +ve add them take 20th element -ve of above sum....
hence avg=0... - 9 years agoHelpfull: Yes(1) No(0)
- option 4) 19
- 9 years agoHelpfull: Yes(0) No(2)
- please tell me elitmus 16th result is declare or not?
- 9 years agoHelpfull: Yes(0) No(0)
- the ans is 19
- 8 years agoHelpfull: Yes(0) No(0)
- 19 is the correct answer
- 8 years agoHelpfull: Yes(0) No(0)
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