158ya @ketan coaching centre approach..
Sigma really?Upvote·0· Reply ·2012-06-05 12:06:15
An ant is at a corner of a cubical room of side a.The ant can move with a constant speed u.The minimum time taken to reach the farthest corner of the cube is
(a)3au (b)√3au (c)√5au (d)(√2+1)au
(According to me, if the ant cannot fly,
then it would have to cover a diagonal of one face and then,move up the opposite edge...
hence, the answer should then be (d)
and, if we consider that the ant flies,(b) would be correct...
given correct answer is (c)...which would only come if we consider that the ant covers the diagonal of one face and then another diagonal of the adjacent face and then,another edge....why should we consider like that ...!!!!)
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6 Answers
1057@anik...
i m assuming that the ant cant fly...
the shortest distance will be the sum of two half diagonals....one running from the top corner to the bottom centre of that face and the second one from that point to the destination we wanted to reach...
a way to think in these type of questions is...
take that cube aur usko pura khol ke ek plane paper bana le....now find the shortest distance between the points given....
158@ketan
ya...got it....thanks....actually mera study room bhi somewhat cube type kaa hi hai....i was thinking of the problem with respect to my room....
ya...these questions are often common....maine iske jaisa hi similar waala problem dekha tha....FTRE mai...
1fiitjee question eh.....?
@ketan typical coaching centre approach....
1581057@all....
manish bhaiya told me this once....
what do i do?
dont use it?