I need help for questions a) and b) unsure how to solve it using this chart. Would i use percentile point formula or percentile rank formula or neither? the answers say for A) 130.5 B) 67, not sure how they got those, could you please explain and show work.

15. The following table represents the data from 86 amateur marathon runners at a recent event. The numbers are the running time expressed in minutes. Class Interval f Cumf Cum % rel f 120-124 1 1 1.16 n/a 125-129 6 7 8.14 n/a 130-134 8 15 17.44 .09 135-139 13 28 32.56 n/a 140-144 15 43 50.00 .17 145-149 12 55 63.96 n/a 150-154 12 67 77.91 n/a 155-159 8 75 87.21 n/a 160-164 6 81 94.19 n/a 165-169 5 86 100 n/a a) You must finish in the top 10% to be eligible for the Boston marathon. How fast do you need to run this race in?

b) If you ran the race in 136 minutes how many people finished behind you?