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

• 20 cows
• 14 years agoHelpfull: Yes(6) No(1)
• 20
• 14 years agoHelpfull: Yes(5) No(1)
• 9
• 14 years agoHelpfull: Yes(3) No(5)
• There is also a simple solution to this problem
  
  24 days 70 cows ==total work done=24*70=1680
  
  60 days 30 cows === total work done= 60*30= 1800
  
  Now see here that total work done must be the same but there is a difference . that difference corresponds to the increasing grass/day ie. work done by grass
  
  work done by grass =1800-1680 =120 (this work is done in (60-24=36 days).
  
  work done by grass per day =120/36= 10/3
  
  now work done by grass in 24 days= (10/3)*24=80
  
  actual work = 1680 -80 = 1600
  
  now work done by grass for 96 days = (10/3)*96== 320
  
  total work required to be done = 1600 + 320 = 1920
  
  cows required = 1920/96 == 20
• 7 years agoHelpfull: Yes(2) No(0)