can this solution be discussed too?

from my analysis

1. This does not talk about the other 200kms at all, hence not giving any solutions

2.

with current speed, it can be written as

s=400/t

where s = current speed and t= current time

if speed is increased by 20, then s=s+20 and time reduces by 1 hr meaning t=t-1

but t=400/s from first equation

so now we have

s+20 = 400/(t-1)

substituting for t in above equation we get

s+20 = 400/((400/s) - 1)

s+20 = 400s/(400-s)

so since it is having a single variable to resolve and to find out the speed, we can then find out the time taken too...

hence possible.

so B

hope this answers....

Note: I sometimes feel i can resolve the problems easily..but when i take a prep-test...i would fail to solve even the simplest...so its pressure which is reducing my efficiency... does anybody else too are facing this?

_________________

Regards,

Harsha

Note: Give me kudos if my approach is right , else help me understand where i am missing.. I want to bell the GMAT Cat

Satyameva Jayate - Truth alone triumphs