Given:
The number of scores, n=20.
The number of test scores less than or equal to 86, N=2.
The percentile rank of 86 is,
[tex]\begin{gathered} \text{Percentile rank=}\frac{Number\text{ of lower scores}}{\text{Total number of scores}}\times100 \\ =\frac{N}{n}\times100 \\ =\frac{2}{20}\times100 \\ =10 \end{gathered}[/tex]Therefore, the percentile rank of 86 is 10.