Official Solution: A shopkeeper at a movie theater concession stand mixes almonds and pistachios in a ratio of 6:5 by weight. The mixture is then sold at $25 per pound, earning a 25% profit. If the cost of almonds for the shopkeeper is $11 more per pound than the cost of pistachios, what is the cost price of almonds per pound? A. $14
B. $20
C. $25
D. $26
E. $29
Assume the total weight of the mixture is 11 pounds. This simplifies the math because the total weight 11 pounds matches the sum of the ratio 6 parts almonds + 5 parts pistachios.
• Almonds: 6 parts of the 11-pound mixture = 6 pounds of almonds.
• Pistachios: 5 parts of the 11-pound mixture = 5 pounds of pistachios.
Let the cost of pistachios per pound be \(p\). Then, the cost of almonds per pound is \(p + 11\).
Thus, the total cost of the 11-pound mixture is:
\(6(p + 11) + 5p\)
The selling price of the mixture is 25 dollars per pound, and the shopkeeper earns a 25% profit. So the cost price of the mixture is \(\frac{25}{1.25} = 20\) dollars per pound, and 20 * 11 for 11 pounds.
So, we get:
\(6(p + 11) + 5p = 20 * 11\)
\(p = 14\)
So, the cost of pistachios is 14 dollars per pound, and the cost of almonds is \(p + 11 = 14 + 11 = 25\) dollars per pound.
Answer: C