Two men start from opposite banks of a river . They meet 340 meters away from one of the banks on forward journey. After that they meet at 170 meters from the other bank of the river on their backward journey. What will be the width of the river (in meters)?

• let p,q are two persons then their speeds be a,b->m/hr
  x----340----------------------|---(d-340)---------y
  in forward journey
  time taken by p=340/a;
  time taken by q=d-340/b;
  in forward journey, time taken by p=time taken by q
  so 340/a=d-340/b
  a/b=340/d-340------------(1)
  after that they continue their journeyand reach other banks
  now in backward journey,
  x---------------(d-170)--------------------------|-----170------y
  distance travelled by p from meet 1 to meet 2 = (d-340)+170
  distance travelled by p from meet 1 to meet 2 =340+(d-170)
  now time taken by p= time taken by q
  (d-340)+170/a=340+(d-170)/b
  (d-340)+170/340+(d-170)=a/b---------(2)
  from 1&2
  340/(d-340)=(d-340)+170/340+(d-170)
  340/(d-340)=d-170/d+170
  340d+57800=d^2-340d-170d+57800
  340d=d^2-510d
  d^2-850d=0
  d(d-850)=0
  d=0 ord=850
  so width of the river is 850
  
  
  
• 10 years agoHelpfull: Yes(16) No(0)
• Let the two opposite ends of the river be X and Y and the distance between them be D meters.(i.e., width = D meters)
  Let P and Q be the two men starting from the opposite banks(i.e., from X and Y respectively).
  Let the speed of P and Q be A and B m/hr .
  
  I meet :
  During I meet, P travels 340m from X while Q travels (D - 340)m from Y.
  Therefore, Time taken for P to travel 340m = Time taken for Q to travel (D - 340)
  Or 340 / A = (D - 340) / B
  Or 340 / (D - 340) = A / B ...(1)
  
  II meet :
  After crossing spot I, both of them proceed in their respective directions, reach banks and return back to cross each other at Spot II which is 170m from Y.
  From Spot I to Spot II, P would had travelled a distance of (D - 340) + 170 m
  From Spot I to Spot II, Q would had travelled a distance of 340 + (D - 170) m
  Time taken by P to travel from Spot I to Spot II will be the same as that of Q from Spot I to Spot II
  
  Therefore, A / (D - 340) + 170 = B / 340 + (D - 170)
  Or (D - 340) + 170 / 340 + (D - 170) = A / B ...(2)
  From equations I and II, we get,
  340 / (D - 340) = (D - 340) + 170 / 340 + (D - 170)
  340 / (D - 340) = D - 170 / D + 170
  By Cross- Multiplying,
  340 (D + 170) = (D - 170) (D - 340)
  340D + 57800 = D2 - 170D - 340D + 57800
  D2 - 850D = 0
  By Factorizing,
  D(D - 850) = 0
  D = 850
  Hence the width of the river = 850 m
• 10 years agoHelpfull: Yes(0) No(0)
• Initial Case: D = S*T
  Second Case: D = (S-200)*(T+1/2)
  Solve both equation u will get t= +-1 so answer is +1
• 4 years agoHelpfull: Yes(0) No(0)