what is the 50th term of term of the series 1,3,6,10,15,21?

• Ans 1275
  The series is like 1,1+2,1+2+3,1+2+3+4,....
  so 50th term wil be 1+2+3+4+....50
  sum of n natural numbers =n*(n+1)/2 where n is 50
  answer wil be 25*51=1275
• 10 years agoHelpfull: Yes(37) No(0)
• Ans : 1275
  The series is like 1,1+2,1+2+3,1+2+3+4,....
  so 50th term will be 1+2+3+4+....50
  sum of n natural numbers =n*(n+1)/2 where n is 50
  answer will be 25*51=1275
  
• 10 years agoHelpfull: Yes(7) No(0)
• 1+2=3
  3+3=6
  6+4=10
  10+5=15
  15+6=21
  21+7=28
  Ans:28
  
• 10 years agoHelpfull: Yes(1) No(14)
• 50(51)/2=1275
  
• 10 years agoHelpfull: Yes(1) No(0)
• 1,1+2,1+2+3.....n so on
  therefore for 50th term=50*(50+1)/2
  1275
  
• 10 years agoHelpfull: Yes(1) No(1)
• ans is 1275
  it is an increasing sequence difference is 2,3,4,5,6,7...
• 10 years agoHelpfull: Yes(0) No(0)
• 1+2=3
  3+3=6
  6+4
  10+5
  15+6
  21+7
• 10 years agoHelpfull: Yes(0) No(0)
• 1,3,6,10....
  the difference between the above numbers is an ap with a=2 and d=1
  2,3,4....
  a50=sum of first 49 terms and the 1st term of the above series
  S49=49/2(2+49)=1225
  a50=1225+1=1226
• 10 years agoHelpfull: Yes(0) No(2)
• T(50)=a+n(n-1)
  1+49*50=2451
  
• 9 years agoHelpfull: Yes(0) No(1)
• 3-1=2 and 3+1=(2)^2
  6-3=3 and 6+3=(3)^2
  .........
  so
  let 49th term be n and 50th term be n+50
  n + n+50=(50)^2
  hence n=1225
  and n+50=1275
• 9 years agoHelpfull: Yes(0) No(0)