Description for Correct answer:
Area of square room = \( \Large (10)^{2} \) = 100 sq

= \( \Large 100\times (100)^{2} \) sq cm

= \( \Large 100\times 100\times 100 \) sq cm

Now, area of tile = \( \Large (50)^{2}=50\times 50 \) sq cm

Number of tiles needed

= \( \Large \frac{Area \ of \ square \ room}{Area \ of \ tile} \)

= \( \Large \frac{100\times 100\times 100}{50\times 50} \) =400

Hence, 400 tiles will be needed.