Q214 / 240 · KCET 2026 · Physics
A car covers the first half of the distance between two places at $40$ km/h and another half at $50$ km/h. The average speed of the car is
- A$45.00$ km/h
- Correct answerB$44.44$ km/h
- C$43.14$ km/h
- D$42.04$ km/h
Solution
Let the total distance be $2d$.
Time taken to cover the first half of the distance is $t_1 = \dfrac{d}{40}$.
Time taken to cover the second half of the distance is $t_2 = \dfrac{d}{50}$.
Total time taken is $t = t_1 + t_2 = \dfrac{d}{40} + \dfrac{d}{50} = \dfrac{9d}{200}$.
Average speed is given by the ratio of total distance to total time.
$v_{avg} = \dfrac{2d}{\dfrac{9d}{200}} = \dfrac{400}{9} = 44.44$ km/h.
Answer: $44.44$ km/h
Time taken to cover the first half of the distance is $t_1 = \dfrac{d}{40}$.
Time taken to cover the second half of the distance is $t_2 = \dfrac{d}{50}$.
Total time taken is $t = t_1 + t_2 = \dfrac{d}{40} + \dfrac{d}{50} = \dfrac{9d}{200}$.
Average speed is given by the ratio of total distance to total time.
$v_{avg} = \dfrac{2d}{\dfrac{9d}{200}} = \dfrac{400}{9} = 44.44$ km/h.
Answer: $44.44$ km/h
Hence, the correct answer is option: 'B'.