Answer: Option C
No; Jamie could not have won 11 games because

Explanation:
Let's call x the number of games that Jamie has won
Let's call y the number of games that Imani has won
We know that Imani has won 5 more games than Jamie.
Then we can say that:

We know that the total number of games that Jamie and Imani have won together is 30.
So

We want to know if it is possible that
.
Then we substitute the first equation in the second and get the following:

Now replace
in the equation and check if equality is met.

Equality is not met, then the correct answer is option C