The speed of train in going from Bhopal to Varanasi is 100 kmph while when coming back from Varanasi to Bhopal, its speed is 80 kmph. What is the average speed during the whole journey? (correct to two decimal places)
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 88.89 kmph
Average speed = 2 × S1 × S2 / (S1 + S2)
Where S1 = Speed when going to from Bhopal to Varanasi = 100 kmpl
S2 = Speed when coming back from Varanasi to Bhopal = 80 kmpl
2 × 100 × 80 / (100 + 80)
16000/180 = 88.89 kmpl