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Numerical Ability
Number System
Mr A took up the sum of natural numbers, by mistaken he add a number twice and find the sum to be 1000.Find the repeated number.
a)23 b)11 c)9 d)10
Read Solution (Total 6)
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- if n=44 then sum of natural numbers =44(44+1)/2
=990
but given sum is 1000
so the number added twice =1000-990=10 ans
- 9 years agoHelpfull: Yes(17) No(2)
- sum of natural number = n(n+1)/2
by hit and trial lets take n=44
(44*45)/2=990
given sum =1000
so number added twice =1000-990=10
ans is 10 - 9 years agoHelpfull: Yes(2) No(0)
- Amswer id d) 10.
Explaination: 45(45-1)/2=990 , so that 10 will be repeat to compute sum 1000. - 9 years agoHelpfull: Yes(2) No(4)
- sum of n natural number is given by n(n+1)/2
so, if we take n=45,then sum=990,
hence, 1000-990=10
10 is added twice
- 9 years agoHelpfull: Yes(2) No(1)
- if n =13
then sum is 91 if we include 9 two time in then we get 100
hence ans is 9 - 9 years agoHelpfull: Yes(0) No(9)
- n(n+1)=2000-2y
y=10
- 8 years agoHelpfull: Yes(0) No(0)
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