A fruit seller had some apples. He sells 40% apples and still has 420 apples. Originally, he had:

Answer: Option D

Suppose originally he had x apples
Then,
$$\begin{array}{rl}& \left(100-40\right)\%\text{of}x=420\\ & \Rightarrow \frac{60}{100}\times x=420\\ & \Rightarrow x=\frac{420\times 100}{60}=700\end{array}$$