mitaliisrani wrote:A man covered a distance of 200 kms partly by train and partly by bus. Had he covered the entire distance by bus, he would have taken 10 hours more and had he covered the entire distance by train, he would have taken 6 hours less. What was the difference between the distances (in kms) covered by him by bus and train?
a)60 b)75 c)50 d)90
OA is B
If the difference between the distances (in km) covered by him by bus and train is x, and if we are free to take for granted more distance covered by train than by the bus and that the train being faster than the bus, then distance covered by train is ½ (200 + x) and distance covered by bus is ½ (200 - x). Furthermore, if b is bus speed and t is train speed, then total time taken was
½ (200 + x)/t + ½ (200 - x)/b.
Since bus takes 10 more hours to cover ½ (200 + x) than the train does, hence
½ (200 + x)/b - ½ (200 + x)/t = 10
Or (1/b - 1/t) = 20/ (200 + x).
And, since bus takes 6 more hours to cover ½ (200 - x) than the train does, hence
½ (200 - x)/b - ½ (200 - x)/t = 6
Or (1/b - 1/t) = 12/ (200 - x).
Equating, we get
20/ (200 + x) = 12/ (200 - x); solving gets me [spoiler]
50[/spoiler], BUT
Please check the OA and cite the source
