A certain distance is covered at a certain speed. If half of this distance is covered in double the time, the ratio of the two speed is :

Answer: Option B

Let the original speed be S₁ and time t₁ and distance be D.
Now,
$$\begin{array}{rl}& \frac{\frac{D}{2}}{2t_1}=S_2\\ & S_2=\frac{D}{4t_1}\text{and}{S}_1=\frac{D}{t_1}\\ & \text{Thus},\\ & \frac{S_1}{S_2}=\frac{4}{1}=4:1\end{array}$$