30% apples out of 450 are rotten, How many apples are in good condition ?

Answer: Option D

Number of rotten apples :
$$\begin{array}{rl}& =30\%\text{ of }450\\ & =\left(\frac{30}{100}\times 450\right)\\ & =135\end{array}$$
∴ Number of good apples = 450 - 135 = 315