Between Two Percentile Ranks

A clinic logs the waiting time of 80 patients. Using the percentile-rank definition from this course,

$\text{percentile rank of } x = \frac{\text{count of values} \le x}{80} \times 100,$

the records show:

• The waiting time 12 minutes has percentile rank 25.
• The waiting time 25 minutes has percentile rank 60.
• Exactly 7 patients waited exactly 12 minutes.

How many patients waited more than 12 minutes but no more than 25 minutes?