jmc

Adding all of the numbers gives us $\frac{11\cdot 12}{2}=66$ as the current total. Since there are $11$ numbers, the current average is $\frac{66}{11}=6$. We need to take away a number from the total and then divide the result by $10$ because there will only be $10$ numbers left to give an average of $6.1$. Setting up the equation: $\frac{66-x}{10}=6.1$ $66-x=61$ $x=5$ Thus, the answer is $\boxed{5}$