A paper studied various aspects of bus service and presented data on travel times from several different routes. The accompanying frequency distribution is for bus travel times from origin to destination on one particular route in Chicago during peak morning traffic.

Class	Frequency	Relative Frequency
15 to <16	4	0.02
16 to < 17	0	0.00
17 to <18	26	.15
18 to < 19	9	9.49
19 to <20	3	6.16
20 to < 21	8	.04
21 to < 22	12	.06
22 to < 23	0.0	0
23 to < 24	0.0	0
24 to < 25	0.0	0
25 to <26	16	.08

Compute (approximately) the percentiles.

a) 90th percentile.

b) 97th percentile.

c) 10th percentile.