To find out how many innings each pitcher for the Stingrays pitched, we start by noting that there are 11 innings in total and there are 3 pitchers.
Let \( x \) be the number of innings each pitcher pitched. Since all three pitchers pitched the same number of innings, we can express the total innings pitched as:
\[ 3x = 11 \]
To solve for \( x \), we can divide both sides of the equation by 3:
\[ x = \frac{11}{3} \]
Thus, each pitcher pitched for \( \frac{11}{3} \) innings. To express this as a mixed number, we can perform the division:
\[ 11 \div 3 = 3 \quad \text{(with a remainder of 2)} \]
This means:
\[ \frac{11}{3} = 3 , \text{whole innings} + \frac{2}{3} , \text{of an inning} \]
Therefore, as a mixed number, the number of innings each pitcher pitched is:
\[ \boxed{3 \frac{2}{3}} \]