in pure milk if 20% replaced by water and in this again 20% is replaced by water and again 20% is replaced by water then what is the proportion of milk in that mixture

• just deduct 20% from 100 = 80,
  
  again reduce 20% of 80 from 80 = 64,
  
  again subtract 20% of 64 from 64 = 51.2
  
  Ans = 51.2 %
• 12 years agoHelpfull: Yes(8) No(4)
• assume pur milk is 100 leters.
  after all these 3 operations, quantity of milk= [100(1-20/100)^3}=[100(80/100)^3]
  =51.2
  so proportin of milk=51.2*100/100=51.2%
  
• 12 years agoHelpfull: Yes(5) No(1)
• apply successive-discounts..1st... (-20-20+{ (-20)*(-20)}/100=-36
  2nd..(-36-20+{(-36)*(-20)}/100=-48.8
  3nd...proporation of milk(100-48.8)=51.2%(ans)
• 8 years agoHelpfull: Yes(0) No(0)