Solution
Step 1
Dalvin's finishing time is normally distributed with a mean of 65 seconds and a standard deviation of 1 second.
[tex]\begin{gathered} \text{Mean }\mu\text{ = 65} \\ Standard\text{ deviation }\sigma\text{ = 1} \end{gathered}[/tex]Step 2
Under the empirical rule, 68% of the results will be within 1 standard deviation.
Step 3
Since the standard deviation is 1 second, 68% of Dalvin's finishing time will be between 63 and 65 seconds.
Final answer
68%