Question

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

• A. $4:1$
• B. $1:4$
• C. $2:1$
• D. $1:2$

Answer 1

The correct option is A $4:1$

Let $x$ km be covered in y hours.

Then, speed $=\frac{x}{y}$ km/hr

In the second case, $\frac{x}{2}$ km is covered in 2y hours.

$\therefore$ New speed $=(\frac{x}{2}\times \frac{1}{2y})km/hr=\frac{x}{4y}km/hr$

$\therefore$ Ratio of speeds $=\frac{x}{y}:\frac{x}{4y}=1:\frac{1}{4}=4:1.$