in a pasture, the grass grows at an even rate. 40 cows can completely eat the grass in 40 days, if there are 30 cows the grass last fot 60 days, for how long it is sufficient for 20 cows
1) 80 2)90 3)100 4)120 5 )none

• Ans: 80Reason:The days will be increased by 20 as the number of cows decreases by 10
• 9 years agoHelpfull: Yes(2) No(0)
• Let I be the initial Grass
  g br the rate of growth of grass per day
  r be the rate of consumption of grass by one cow in one day
  
  For 40 cows
  I+40g=40*40r -------------------------1
  for 30 cows
  I+60g=30*60r --------------------------2
  Then for 20 cows
  I+ng=20*n*r -------------------------3
  where n is the no of days
  
  Subtracting the first two equation and dividing it by 20
  g=10r
  Subtracting the equations 2 and 3 and subustituting the value of g
  
  we get
  n=120
• 8 years agoHelpfull: Yes(2) No(0)
• ans-120days
• 11 years agoHelpfull: Yes(1) No(4)
• 40 cow can completely eat the grass in 40 days it means there is 40 * 40 = 1600 cow are able to eat the food
  
  for 20 cows the solution is like this-
  20*x=1600
  (where x is the no of days)
  x=80
• 8 years agoHelpfull: Yes(1) No(0)
• 80 no of days inc by 20 as cow dec by 10
• 9 years agoHelpfull: Yes(0) No(0)