Tristan paid $17.50 to buy 2 pounds of peanuts and 3 pounds of cashews. Rivka paid $19.00 to buy 5 pounds of peanuts and 2 pounds of cashews. If both people paid the same price per pound, what was the price per pound for the cashews?
Let x be the price per pound for peanuts.
Let y be the price per pound for cashews.
2x + 3y = 17.50
5x + 2y = 19.00
Solve the second equation for x: x = (19.00 - 2y) / 5
Substitute the expression for x in the first equation: 2 * (19.00 - 2y) / 5 + 3y = 17.50
Multiply both sides by 5 to eliminate fractions: 4 * (19.00 - 2y) + 15y = 87.50
Multiply through the parentheses: 76.00 - 8y + 15y = 87.50
Combine like terms: 7y = 11.50
Divide both sides by 7 to solve for y: y = 11.50 / 7 = 1.643 approximate to 1.64 dollars.
Therefore, the cashews cost $1.64 per pound. Answer: \boxed{1.64}.