If anyone remember this question asked in elitmus ppr of 22nd december.
Q. A man covers certain distance in time T with velocity V.If he covers 30km of the distance with same speed and remaining with 2V/5 then it takes 45 min more than time T.And if he covers 45km of distance with same speed and remaining with 2V/5 then it takes 36 min more then the original time.what is it initial velocity V.

Option
a)45
B)60
c)90
d)150

• ans:150;
  Let Distance=D, therefore V=(D/T) or T=(D/V);
  now from the first condition we have,
  t1=(30/v),t2=((D-30)/(2V/5))and t1+ t2= T+(45/60);
  (30/v)+((D-30)/(2V/5)) = (D/V)+(45/60); after solving this equation we will have
  2D-v=60; -----(1)
  
  similarly, from the 2nd Condition
  t1=(45/v),t2=((D-45)/(2V/5))and t1+ t2= T+(36/60);
  (45/v)+((D-45)/(2V/5))=(D/V)+(36/60);after solving this equation we will have
  5D-2V=225; -------(2)
  
  after solving equation (1) & (2) V=150;
  
  
• 10 years agoHelpfull: Yes(37) No(1)
• let time T, Velocity V and D=VT
  30 km at the speed of V will take 30/V hour and at (2/5) of V = 2V/5 speed for (VT - 30) it will take (VT - 30)/(2V/5) hours
  Now T + 45/60 = (30/V) + (VT - 30)/(2V/5)-------(1)
  now acc. to 2nd Cond. he covers 45km of distance with same speed and remaining with 2V/5 then it takes 36 min more than the original time.
  45 km on V speed and (2/5 V speed) for (VT - 45)
  Time = (45/V) + (VT - 45)/(2V/5) = T + 36/60------(2)
  (1)-(2)
  =>9/60= -15/V+75/2V
  =>9/60=1/V[-30+75/2]
  =>9/60= 45/2V
  =>V=150
  
• 10 years agoHelpfull: Yes(5) No(1)
• d)150 is it correct?
• 10 years agoHelpfull: Yes(0) No(2)
• yes 150 is correct
  
• 10 years agoHelpfull: Yes(0) No(2)