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

• 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
  
• 8 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
• 8 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.
• 8 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
  
• 8 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
• 8 years agoHelpfull: Yes(0) No(9)
• n(n+1)=2000-2y
  y=10
  
• 8 years agoHelpfull: Yes(0) No(0)