Question

A series of books is published at 4-year intervals. When the fifth book is issued, the sum of the publication’s years will be 10,020. When was the first books published?

Answer 1

The first book was published in 1816.

Explanation:

A series of books is published at 4-year intervals.

This means that:

The first book is published at year x.

The second book is published at year x + 4.

The third book is published at year x + 4 + 4 = x + 8

The fourth book is published at year x + 8 + 4 = x + 12

The fifth book is published at year x + 12 + 4 = x + 16

When the fifth book is issued, the sum of the publication’s years will be 10,020.

This means that:

`x + x + 4 + x + 8 + x + 12 + x + 16 = 10020`

`5x + 40 = 10020`

When was the first books published?

This is x. So

`5x + 40 = 10020`

`5x = 9080`

`x = (9080)/(5)`

`x = 1816`

The first book was published in 1816.