Grass in lawn grows equally thick in uniform rate. It takes 24 days for 70 cows and 60 days for 30 cows to eat the whole grass. how many cows are needed to eat the grass in 96 days?

• 0 cows
  
  g - grass at the beginning
  r - rate at which grass grows, per day
  y - rate at which one cow eats grass, per day
  n - no of cows to eat the grass in 96 days
  
  From given data,
  g + 24*r = 70 * 24 * y ---------- A
  g + 60*r = 30 * 60 * y ---------- B
  g + 96*r = n * 96 * y ---------- C
  
  Solving for (B-A),
  (60 * r) - (24 * r) = (30 * 60 * y) - (70 * 24 * y)
  36 * r = 120 * y ---------- D
  
  Solving for (C-B),
  (96 * r) - (60 * r) = (n * 96 * y) - (30 * 60 * y)
  36 * r = (n * 96 - 30 * 60) * y
  120 * y = (n * 96 - 30 * 60) * y [From D]
  120 = (n * 96 - 1800)
  n = 20
  
  Hence, 20 cows are needed to eat the grass in 96 days.
• 12 years agoHelpfull: Yes(51) No(2)
• 18 cows
  widthe hepl of formula
  m1d1h1/w1=m2d2h2/w2
• 12 years agoHelpfull: Yes(4) No(9)
• answer: 18..is correct
• 12 years agoHelpfull: Yes(1) No(2)
• yes, APARNA u r correct.......!!!!!!!!!!!
  ans is 18
• 12 years agoHelpfull: Yes(1) No(3)