A series of books was published at ten years intervals. When the 10th book was issued the sum of the publication year was 19,560.when was the first book published a)1911 b)1910 c)1914 d)1909

• Sum of A.P. Series, S= (n/2)[2a+(n-1)d]....(1)
  here, n=10 d=10 S= 19560, a=first term
  put all the values in (1)
  19560=(10/2)[2a+(10-1)10]
  19560=5[2a+(9*10)]
  19560=10a+450
  19560-450=10a
  19110/10=a
  a=1911 which is the year when first book was published
• 8 years agoHelpfull: Yes(23) No(0)
• let 1st book published at year=x
  x+(x+10)+(x+20)+(x+30)+.......++(x+90)=19560
  10x+450=19560
  x=1911
• 8 years agoHelpfull: Yes(13) No(0)
• ardham avvale ra
• 8 years agoHelpfull: Yes(1) No(2)
• initial x, 10th x+90 sum of the publication year 10x+450=19560 ;10x=19110
  x=1911 (first book)
• 2 years agoHelpfull: Yes(0) No(0)