20 litres of mixture of acid and water contain 10% water. How much water should be added so that percentage of water becomes 20% in this mixture?

a) 2 L
b) 3 L
c) 2.5 L
d) 4 L

• 2.5L is Exact answer...
  because in 20 litres 2+18
  for 22.5 litres 20% of water means 4.5+remaining 18 litres acid 80%........
• 8 years agoHelpfull: Yes(6) No(5)
• ans - a) 2 L
  explaination )
  total mixture =20ltr
  water contain = 10% of 20ltr => 2ltr water
  it means 18ltr is acid in that mixture
  we have to make 20% water so..20% of 20 = 4ltr water must be there in the new mixture
  we have already 2 ltr water so we have to add 2 ltr more
  so ans => a)2ltr
• 8 years agoHelpfull: Yes(4) No(5)
• ans-c)2.5
  total mixture=20 ltr
  water=20*(10/100)=2
  let x ltr water should be added,
  so (2+x)=(20+x)*(20/100)
  =>(2+x)=(20+x)*5
  =>x=2.5 ltr
• 8 years agoHelpfull: Yes(3) No(1)
• Answer should be 2 l. H20 will be 2l and acid will be 4 l. Now consider water present in final solution as x. therefore, 18+x * 20/100 = x. solving for x, we get 4 l. Therefore, extra water added is 2 l.
• 8 years agoHelpfull: Yes(1) No(0)
• 10% of 20 litres is 2 litres.
  To make it 20% water, you'll have to add 'x' litres of water to the mixture.
  
  x+2/(x+20) = 20/100
  5(x+2)=x+20
  4x=10
  x=10/4
  x=2.5
  
  So, if you add 2.5 litres of water to the mixture, you'll have 20% of water in the 22.5 litres of mixture.
• 8 years agoHelpfull: Yes(1) No(0)
• in 20 litres it contains=2 ltrs water and 18 ltrs acid
  
  
  to become 20% of water in mixture =20/2+x=4
  x=3ltrs
• 8 years agoHelpfull: Yes(0) No(6)
• 20lts=100%;
  10%water remaing 90%acid.
  10%=2lts
  then 20%=2*2=4lts
• 7 years agoHelpfull: Yes(0) No(0)
• d )4 L
  10% of 20 litres is 2 litre of water
  then 20 % of water is 4L
• 7 years agoHelpfull: Yes(0) No(0)