A series of books was published at seven-year intervals When the seventh book was issued the sum of the publication

You can solve it by AP.Sum of n terms in a.p. is Sn=n/2[2a+(n-1)d].We have Sn=13542,n=7,d=7.On substituting and solving,we get answer as 1911.
10 years agoHelpfull: Yes(20) No(0)
x+(x+7)+(x+14)+(x+21)+(x+28)+(x+35)+(x+42)=13524
=>7x+147=13524
7x=13377
x=1911
so,1st book was published at 1911
10 years agoHelpfull: Yes(3) No(1)
It is an arithmetic progression.
Year of 1st book published = a
d=7, Sn= 13524, n=7.
Sn= n/2{2a+(n-1)d}
By solving for a, Answer is 1911.
10 years agoHelpfull: Yes(2) No(2)
1911
s(7)=7/2[(2*a)+6*7]
10 years agoHelpfull: Yes(2) No(0)
1929

x+(x+1)+(x+2)+...+(x+6)=13524
then x=1929
10 years agoHelpfull: Yes(1) No(11)
as published at 1911
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A series of books was published at seven-year intervals. When the seventh book was issued, the sum of the publication years was 13,524. When was the first book published?