To find the total amount Samuel spent at the market on both days, we need to calculate the cost for each day separately and then add them together.
Day 1:
- Samuel bought 3 pounds of apples at \(x\) dollars per pound, so the cost of apples is: \[ 3x \]
- He also bought 2 bags of spinach at \(y\) dollars each, so the cost of spinach is: \[ 2y \]
- Therefore, the total amount spent on Day 1 is: \[ 3x + 2y \]
Day 2:
- Samuel bought 5 pounds of apples at \(x\) dollars per pound, so the cost of apples is: \[ 5x \]
- He also bought 3 bags of spinach at \(y\) dollars each, so the cost of spinach is: \[ 3y \]
- Therefore, the total amount spent on Day 2 is: \[ 5x + 3y \]
Now, we add the total amounts from both days: \[ (3x + 2y) + (5x + 3y) = 3x + 5x + 2y + 3y = 8x + 5y \]
Thus, the expression that represents the total amount Samuel spent at the market on both days is: \[ \boxed{8x + 5y} \]