Question

Half the books you own are mysteries. one third are nonfiction. the other four books are science fiction. how many of your books are mysteries?

Answer 1

The number of mystery books = 12

Explanation:

let n be the total number of the books.

→ “Half the books you own are mysteries” means (n÷2) are mysteries

→ “one third are nonfiction” means (n÷3) are non fiction

→ 4 books are sc-fiction

………………………………………

We can form this equation:

`(n)/(2) +(n)/(3) +4=n`

`\Longrightarrow \left( (1)/(2) +(1)/(3) \right) n+4=n`

`\Longrightarrow (5)/(6) n+4=n`

`\Longrightarrow 4=n-(5)/(6) n`

`\Longrightarrow 4=(1)/(6) n`

`\Longrightarrow 4*6= n`

`\Longrightarrow n=24`

………………

Therefore

The number of mystery books = n÷2 = 24÷2 = 12