Question

A car covers 20 km in 40 mins while a bike covers 20 km in 30 mins. What is the difference in their rates?

• A. $\frac{1}{3}\text{km/min}$
• B. $\frac{1}{5}\text{km/min}$
• C. $\frac{1}{6}\text{km/min}$
• D. $\frac{2}{5}\text{km/min}$

Answer 1

The correct option is C $\frac{1}{6}\text{km/min}$

Given,
A car covers 20 km in 40 mins.
$\therefore$ in one minute, it will cover
$=\frac{20}{40}=\frac{1}{2}\text{km/min}$

Again, a bike covers 20 km in 30 mins.
$\therefore$ in one minute, it will cover
$=\frac{20}{30}=\frac{2}{3}\text{km/min}$

So, the difference in their rate or speed
$=\frac{2}{3}-\frac{1}{2}=\frac{1}{6}\text{km/min}$