Grass in lawn grows equally thickand in a uniform rate. It akes 24 days for 70 cows and 60 for 30 cows . How many cows can eat away the same in 96 days?

a) 18
b) 20
c) 21
d) 19

• I think this approach is very long to solve this problem i try to reduce some step
  g= grass initially, r= rate at which grass grow/day, c= cow eat grass/day
  g+24r=70*24c=1680c-----------1
  g+60r=60*30c=1800c--------->g=1800c-60r----------------2
  by solving this 2 equation we have relation c=(3/10)r-------------3
  g+96r=96nc
  =>96nc=1800c-60r+96r=1800c+36r=1800c+120c=1920c
  =>n=20
• 8 years agoHelpfull: Yes(16) No(8)
• x = quantity of grass initially present.
  k = rate of increase of grass per day.
  y = quantity of grass that each cow eats per day.
  x + 24k = 24*70y
  x + 60k = 60*30y
  Now let m cows needed to finish complete the task.
  x + 96k = 96*m*y.
  Find x and k in terms of y and substitute in the final expression.
• 8 years agoHelpfull: Yes(3) No(2)
• plz explain againnn....clearly
• 8 years agoHelpfull: Yes(2) No(0)
• Plzz anyone xplain these above problem clearly!!!
• 7 years agoHelpfull: Yes(2) No(0)
• 20 cows....
• 8 years agoHelpfull: Yes(1) No(4)
• Let us imagine that 1 cow eats 1kg per day.
  70 cows can eat 70kg in a day. Total quantity of grass eaten in 24 days = 24*70 = 1680kg
  1680 = Initial quantity of grass + quantity of grass increased in 24 days.
  1680 = Q + 24x
  
  Similarly in second case
  
  1800 = Q + 60x
  
  By solving both equations, we get
  x = 10/3
  
  Q = 1680 - 24(10/3)
  Q = 1600
  
  Total quantity of grass available in 96 days = 1600 + 96(10/3)
  = 1920
  
  Number of cows required = N
  
  1920/N should be equal to 96
  N = 20
• 5 years agoHelpfull: Yes(1) No(0)