Question

A series of book was published at seven year intervals. When the seventh book was publishad the total sum of publication year was 13, 524. First book was published in ?

Answer 1

Answer:

First book was published in 1911

Step-by-step explanation:

A series of book was published at seven year intervals. When the seventh book was publishad the total sum of publication year was 13, 524. First book was published in ?

Let say first book published in X yeaa

Next Book Published in X + 7 Years

and so on

This forms an AP

a = X   d = 7   n = 7

Sum =  (n/2)(a  + a + (n-1)d)

13524 = (7/2)(X + X  + 6*7)

=> 13524 = 7 ( X + 21)

=> 1932 = X + 21

=> X = 1911

First book was published in 1911

Answer 2

Answer:

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