A series of book was published at 7 year intervals.when the 7th book was issued the sum of publication year is 13524.when was the 1st book published ?
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16
the years at which books are published are terms of AP where
let first term a be x;
common difference (d) =7
number of terms(n)=7
sum of seven terms(S7)=13524
n/2[2a+(n-1)d]=13524
7/2[2x+6(7)]=13524
2x+6(7)=3864
x=1911
therefore the first book was published in 1911
let first term a be x;
common difference (d) =7
number of terms(n)=7
sum of seven terms(S7)=13524
n/2[2a+(n-1)d]=13524
7/2[2x+6(7)]=13524
2x+6(7)=3864
x=1911
therefore the first book was published in 1911
Answered by
5
Answer:
Step-by-step explanation:
common difference (d) =7
number of terms(n)=7
sum of seven terms(S7)=13524
n/2[2a+(n-1)d]=13524
7/2[2x+6(7)]=13524
2x+6(7)=3864
x=1911
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