Q. Milk and cream contain different percents of butterfat. How much 2% milk needs to be mixed with how much 35% cream to give 20 L of 15% cream.
Set up equations: Set up the equation based on the percentages of butterfat in each component.Let x be the amount of 2% milk and y be the amount of 35% cream.We know that the total volume should be 20 liters, so:x+y=20
Second equation: Set up the second equation based on the butterfat content.The total butterfat from the milk and cream should equal the butterfat in the final mixture:0.02x+0.35y=0.15×20
Simplify equation: Simplify the butterfat equation. 0.02x+0.35y=3
Solve system: Solve the system of equations using substitution or elimination.From x+y=20, express y in terms of x:y=20−xSubstitute y in the butterfat equation:0.02x+0.35(20−x)=3
Substitute and solve: Distribute and combine like terms.0.02x+7−0.35x=3−0.33x+7=3
Combine terms: Solve for x.−0.33x=3−7−0.33x=−4x=−0.33−4x=12.12
Find x: Find y using the value of x.y=20−12.12y=7.88
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