A candy distributor needs to mix a 20 fatcontent chocolate w
     A candy distributor needs to mix a 20% fat-content chocolate with a 50% fat-content chocolate to create 100 kilograms of a 41% fat-content chocolate. How many kilograms of each kind of chocolate must they use?  They must mix  Kilograms of the 20% chocolate and  Kilograms of the 50% chocolate. 
  
  Solution
Let x kgs of 20% fat content
Let y kgs of 50% fat content are mixed to get 41% fat xontent
Given: x+y = 100 ----(1)
0.2x +0.5y = 41 -----(2)
Solve equations 1 and 2 to get x and y:
Multiply equation 1 by 0.2:
0.2x +0.2y = 20
0.2x +0.5y = 41
-------------------------- (subtract the two equations)
-0.3y = -21
y = 21/0.3 = 70 kgs of 50% fat content
x = 100- 70 = 30 kgs of 20% fat content

