Distance between A and B is 80 kms. A bus left A at constant speed towards B.30 mins later car left from A to B. Car overtook the bus in 30 mins and continued towards B.With out stopping at B, the car turned back and again encountered the bus 80 mins after he had left A. Speed of bus?
Ans:40 kmph
Plz post the method
My method(its not working though
)
:banghead:
Speed of Bus=B
Speed of Car=C
Since bus left 1/2 hr early distance covered by bus is B/2 kms
Now car over takes the bus in 1/2 hr
So (B/2)/(C-B) = 1/2
=>C=2B
When the car overtakes the bus bus would have covered distance of B kms
So remaining distance is 80-B
when car reaches point B bus would have covered half of 80-B
So remaining is (80-B)/2
Given total time car takes to meet bus for second time = 80 mins
So 80/C + /(C+B)= 80 mins
=> 80/2B + /(2B+B)= 4/3 hr
Solving this I get sum stupid values for B
:banghead:
Think bhai, can yu point out my mistake
In bold part, you have made a small mistake.. They meet for the first time after travelling certain distance..
So, we need to remove that from 80 first...
Here is my appraoch:
My answer is 80/3 kmph.
Say, they meet for first time after 'x' km.
Now, car and bus together travel 160 km.
Excluding first x of each, in remaining distance, car travels double the distance of bus.
Now, remaining distance = 160-2x
Bus will travels 1/3 of it and car will trave; 2/3 of it.
So, bus travels (160-2x)/3 = (160/3 - 2x/3) in 80 mins.
Now, bus takes 60 mins for x. So, it will take 40 mins from 2x/3.
So, bus travels 160/3 in 40+80 i.e 120 mins.
So, in one hour bus will travel 80/3 km.
So, speed of bus = 80/3 kmph.