Question

Find the number of natural numbers between $7^2$ and $9^2$.

• A. 29
• B. 30
• C. 31
• D. 32

Answer 1

The correct option is C 31

Number of natural numbers between $n^2$ and $(n+1{)}^2$ is 2n.
So, number of natural numbers between $7^2$ and $8^2$ is 14.
So, number of natural numbers between $8^2$ and $9^2$ is 16.
$8^2$ is also in between them.
So, total = 14 + 1 + 16 = 31