Let the prices of the small, medium, and large cups be \(2x\), \(5x\), and \(y\) respectively.
From the given information:
\((2x)(5x)(y) = 800 \quad \text{(1)}\)
When the prices of the small and medium cups are increased by 6, the product becomes:
\((2x + 6)(5x + 6)(y) = 3200 \quad \text{(2)}\)
Divide Equation (2) by Equation (1):
\(\frac{(2x + 6)(5x + 6)(y)}{(2x)(5x)(y)} = \frac{3200}{800}\)
This simplifies to:
\(\frac{(2x+6)(5x+6)}{10x^2} = 4\)
Multiply both sides by \(10x^2\):
\((2x+6)(5x+6) = 40x^2\)
Expand the left side:
\(10x^2 + 30x + 12x + 36 = 10x^2 + 42x + 36\)
Rearrange the terms:
\(10x^2 + 42x + 36 = 40x^2\)
\(30x^2 - 42x - 36 = 0\)
Divide by 2:
\(15x^2 - 21x - 18 = 0\)
\((5x + 6)(3x - 2) = 0\)
The possible values for \(x\) are \(x = -\frac{6}{5}\) or \(x = 2\).
Since a price cannot be negative, we select \(x = 2\).
Substitute \(x = 2\) into Equation (1):
\((2 \cdot 2)(5 \cdot 2)(y) = 800\)
\(4 \cdot 10 \cdot y = 800 \Rightarrow 40y = 800 \Rightarrow y = 20\)
The sum of the prices is \(2x + 5x + y = 4 + 10 + 20 = \boxed{34}\).