Final answer:
Approximately 80.65 pounds of dried fruit will be needed to make the mix, according to the given ratios and prices.
Step-by-step explanation:
To find the amount of dried fruit needed, we can set up a ratio using the prices of the mixed nuts and dried fruit. Let's call the weight of dried fruit needed x. The cost of the mixed nuts is $10.25 per pound, and the cost of the dried fruit is $3.35 per pound. The finished trail mix costs $6.80 per pound. We can set up the following equation:
(81 pounds of mixed nuts) / ($10.25 per pound) + (x pounds of dried fruit) / ($3.35 per pound) = (81 pounds + x pounds) / ($6.80 per pound)
To solve for x, we can cross multiply and solve for x:
(81 * $6.80) + ($3.35 * x) = ($10.25 * 81) + ($6.80 * x)
Simplifying the equation:
551.8 + $3.35x = 830.25 + $6.80x
Subtracting $3.35x and 551.8 from both sides:
$6.80x - $3.35x = 278.45
Combining like terms:
$3.45x = 278.45
Dividing both sides by $3.45:
x = 80.65
So, approximately 80.65 pounds of dried fruit will be needed to make the mix.