Question

In a hall, 225 chairs are arranged in such a way that the number of rows is equal to the number of columns. If one more row and column of chairs is added, find the new number of chairs in the hall.

• A. 246
• B. 256
• C. 265
• D. 276

Answer 1

The correct option is B

256

Initially, since the number of rows is equal to the number of columns, it is forming a square.

Let number of row be ${}^{\prime }{a}^{\prime }$

Total number of chairs $=a^2$

$\therefore a^2=1225$

$a=\sqrt{225}$

$a=\sqrt{3\times 3\times 5\times 5}$

$a=\sqrt{3^2\times 5^2}$

$a=3\times 5=15$

Now, if we add 1 row and 1 column, number of row and column becomes 15 +1 = 16.

Now total number of chairs $=16\times 16={16}^2=256$