Question

The number of non-square numbers between 1225 and 1370 (both inclisive) is:

• A. 142
• B. 143
• C. 144
• D. 145

Answer 1

The correct option is B 143

There are 2n non-square numbers between $n^2$ and $(n+1{)}^2$.
Now, $1225={35}^2,1370={37}^2+1$.
From the above formula, there are 70 non-squares between ${35}^2$ and ${36}^2$, and 72 non-squares between ${36}^2$ and ${37}^2$.

Including 1370, thus, there are a total of 143 non-square numbers between 1225 and 1370.