13more clarity aneesh... its not my doubt, its my challenge...!!!
67 lines are drawn such that no two of them are parallel and no three are concurrent. Now 68th line is drawn parallel to 67th line. Find the number of regions formed in the plane...
[Logical explanation is must]
(ans wid explanation will be given after 1week... )
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UP 0 DOWN 0 2 8
8 Answers
13dat would have been better... [4]
no prob... kabhi kabhi expected response nahi miltha... next tym jyothishy se pooch kar challenge post karunga... so dat i may get d expected response... [3] [6]
9maq got it
at any arrangement of n lines if another line is drawn acc to cond abv , n+1 new regions are created ( 4 evry intersecting pt a region plus one more due to end effect visualise and ull get that )
so by tn+1 - tn = n+1 u get tn = n(n+1)/2 + 1 cos t1= 2
upto 67 use this formula
wen a parralel line comes , it intersects only at 66 pts so 67 more xtra regions due to this final ans
is 68 + 67X68/2
aneesh ans and mine differ by one whos right