Example

Solving a Mixture Word Problem: Trail Mix (Raisins and Nuts)

Apply the seven-step problem-solving strategy, the mixture model, and the known-total technique to a mixture word problem involving food products measured by weight.

Problem: Henning is mixing raisins and nuts to make 2525 pounds of trail mix. Raisins cost $4.50 a pound and nuts cost $8 a pound. If Henning wants his cost for the trail mix to be $6.60 a pound, how many pounds of raisins and how many pounds of nuts should he use?

  1. Read the problem and identify the two ingredient types: raisins (worth $4.50 per pound) and nuts (worth $8 per pound). The total mixture is 2525 pounds at a target cost of $6.60 per pound.
  2. Identify what to find: the number of pounds of raisins and the number of pounds of nuts.
  3. Name the unknowns using a single variable. Because the total weight is known, use the known-total technique. Let x=x = the number of pounds of raisins. Then the number of pounds of nuts is 25x25 - x. Organize the information in a table:
TypeNumber of PoundsPrice per pound ($)Total Value ($)
Raisinsxx4.504.504.50x4.50x
Nuts25x25 - x888(25x)8(25 - x)
Trail mix25256.606.6025(6.60)=16525(6.60) = 165
  1. Translate into an equation. The value of the raisins plus the value of the nuts equals the value of the trail mix: 4.50x+8(25x)=1654.50x + 8(25 - x) = 165

  2. Solve the equation:

  • Distribute 88: 4.50x+2008x=1654.50x + 200 - 8x = 165
  • Combine like terms: 3.50x+200=165-3.50x + 200 = 165
  • Subtract 200200 from both sides: 3.50x=35-3.50x = -35
  • Divide both sides by 3.50-3.50: x=10x = 10 Find the number of pounds of nuts: 2510=1525 - 10 = 15.
  1. Check: 4.50(10)+8(15)=?25(6.60)4.50(10) + 8(15) \stackrel{?}{=} 25(6.60) 45+120=?16545 + 120 \stackrel{?}{=} 165 165=165165 = 165 \checkmark

  2. Answer: Henning mixed 1010 pounds of raisins with 1515 pounds of nuts.

This example demonstrates that the mixture model (extamountextvalue=exttotalvalue ext{amount} \cdot ext{value} = ext{total value}) applies to products sold by weight. The known-total technique produces the expression 25x25 - x for the second ingredient, and solving the equation involves working with decimals.

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Updated 2026-05-02

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