Another Method:
When half of the distance is being covered at a speed X and the other half at a speed of Y, then, the Average speed is given by 2XY/(X+Y)For this question, X = 40 Kmph and Y = 30 Kmph
So, Average speed = 2 x 40 x 30 / (40+30) = 240/7 Kmph
Now, Total distance covered would be Speed (average) x Time. Since, there was a waiting period of an hour: Time must be 7 hours (8-1).
Total Distance = 240/7 x 7 = 240 km
DONT forget that this distance is for 2-way, divide this by 2 for 1-way i.e. 120 km
Hence, option B
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I hope this helps!
Regards:
Karun Mendiratta
Founder and Quant Trainer
Prepster Education, Delhi, Indiahttps://www.instagram.com/prepster_education/