<PRE><B>Question 193463</B>
1) 15 l - 100%
   x  l - 20%
x=(15*20)/100 = 3 l  mixture = 15 l+3 l = 18 l
   P= (3 * 100)/ 18= 100 /6 = 16.66%

2)  x+y =50
  8x+18y=50*14

   x+y=50
   8x+18y=700
 
   18x+18y=900
    8x+18y=700
 
   10x=200  x=20kg   p=(20/50)*100=40%


3)     20  - 90%  =18kg
Add     x   - 0%    0kg

    20+x  - 100%
    18    -  75%

   (20+x)*75= 18*100
   x=4 kg 

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