What is the next number of the
following sequence
1, 3, 6, 10, 15,.......

• it is of the form n(n+1)/2
  1(2)/2 = 1
  2*3/2 = 3
  3*4/2 = 6
  4*5/2 = 10
  5*6/2 = 15
  6*7/2 = 21
  
  so the next number will be 21
• 10 years agoHelpfull: Yes(1) No(0)
• 3-1=2
  6-3=3
  10-6=4
  15-10=5
  next is 21 i.e 21-15=6
  
• 10 years agoHelpfull: Yes(0) No(0)
• 1 3 6 10 15 21
  +2 +3 +4 +5 +6
• 10 years agoHelpfull: Yes(0) No(0)