Question

Rakesh completes a certain journey by car. If he covered $30\%$ of the distance at the speed of $20$ km/hr, $60\%$ of the distance at $40$ km/hr, and the remaining distance at $10$ km/hr, then his average speed is

• A. $25$ km/hr
• B. $28$ km/hr
• C. $30$ km/hr
• D. $33$ km/hr

Answer 1

The correct option is A $25$ km/hr

Let the total distance be $x$ km.
Average speed $=\frac{\text{Total distance covered}}{\text{Total time taken}}$
$=\left(\frac{x}{\frac{3x}{200}+\frac{6x}{400}+\frac{x}{100}}\right)$
$=\frac{400x}{6x+6x+4x}$
$=25$ km/hr