There is N odd number of milestones are to be paint. Distance between the milestones is 100m .Painter can carry only 1 bottle at a time empty or with paint . He has to start with centre of the the milestone and after painting the particular milestone he has to return back the centre milestone. Again he will take new paint bottle for painting next milestone and so on …. Finally he travelled 130 Km . Find the number of milestones N. a. 26 b.51 c. 65 d. 260

• The answer is option b-51.
  EXPLANATION:
  1km=1000m. so,130km=130000metres.
  Consider a centre point as 26.Now LHS and RHS are symmetrical. Considering only RHS,
  each milestone consumes metres in the order of 100,200,300,400,............,2500 to reach forward. and to reach the centre milestone again it took the same order 100,200,300,400,......2500.
  so, on adding all those as follows:
  100+20+300+400+500+600+.....+2500+100+200+300+400+....+2500=65000metres.
  This is for RHS. And for LHS=65000 metres. On addition,
  65000+65000=130000metres.
  so, the answer is 51...
• 10 years agoHelpfull: Yes(15) No(0)
• we knw that this is a symmetrical fig.
  so total distance he covered is 130*1000=13000
  in one side he travell 13000/2= 65000
  when we take a look on option only option 51 is corect because its half (51-1)/2
  divide 65000 completly
• 10 years agoHelpfull: Yes(4) No(2)
• let n=2x +1
  
  |___|___|....._|___|___|..........___|___|___|
  x x-1 x-2 1 0 1 x-2 x-1 x
  above fig is of mile stone from both side of 0 to x
  concider one side
  0-1-0 100 up 100 down =200
  0-2-0 200 up 200 down =400
  similary
  0-x-0 x00 up x00 down =2*x00
  
  Toatal distance one side = 200(1+2+3+....x)....[A]
  total distance both side = 2*A
  
  it is case of just summation of an ap with C.d =1 till n=x
  which gives
  n^2 -1 =2600
  n^2=2601
  n=51
• 10 years agoHelpfull: Yes(3) No(0)
• let n be milestones on left side and n on right side.So 130000/2=2*n/2(2*100+(n-1)*100).Solving we get n=25.so total milestones=25+25+1=51
• 10 years agoHelpfull: Yes(2) No(1)