To find out how many problems Myra answered correctly, we first need to calculate 86% of the total number of problems on the quiz, which is 50.
We can calculate it as follows:
\[ \text{Correct Answers} = \text{Total Problems} \times \text{Percentage Correct} \]
Substituting the values:
\[ \text{Correct Answers} = 50 \times 0.86 \]
Now, let's perform the multiplication:
\[ 50 \times 0.86 = 43 \]
Thus, Myra answered 43 problems correctly.