there ia truck which should reach some place at 11`o clock , if it travels with 30 mph it reaches i
hour before , if it travles with 20 mph it reaches 1 hour late. what is the distance it must be travlled and what is the speed it must maintain to rech at exact time?

• i think i must be like this
  let the distance be d
  d/30=t-1
  d/20=t+1
  on dividing above we get
  3/2=(t+1)/(t-1)
  t=5hrs.
  so d=120miles
  
• 13 years agoHelpfull: Yes(3) No(2)
• let the distance d;
  let the starting time t;
  av.vel v=d/11-t;
  for reaching before:30=d/10-t;
  for reaching late:20=d/12-t;
  30/20=12-t/10-t;
  t=6'o clock;
  d=120m;
  v=24;
  
  
• 13 years agoHelpfull: Yes(1) No(2)
• distance is 120miles of and speed is of 24m/h
• 12 years agoHelpfull: Yes(1) No(2)
• find the average speed
  i.e.
  2*30*20/20+30
  =24mph
  now find the no.which is divisible by 20.30 &24
  and that no.is 120.
  so, distance is 120m and speed must be 24mph
• 9 years agoHelpfull: Yes(1) No(0)
• we know, speed proportional to 1/time(where distance is constatnt)
  
  so, let's time taken is x hr
  then,
  30/20=(x+1)/(x-1)
  => x=5
  
  so, it travels for (5-1)=4 hr with a velocity of 30ml/hr
  total distance=(30*4)=120ml
  it must maintain a velocity of (120/5)=24ml/hr
• 9 years agoHelpfull: Yes(1) No(0)