What is the sum of all the integers which are multiples of 7 from between 200 to 400?

• 
  Arithmetic progression:
  
  first term 'a'= 203
  last term 'l'= 399
  common difference 'd'=7
  no.of terms = 400/7 - 200/7 = 57-28 = 29
  sn=n/2(2a+(n-1)d)
  =29/2(2(203)+(28)7)
  =14.5(406+196)
  =14.5(602)
  =8729
  
• 11 years agoHelpfull: Yes(1) No(0)