Answer:
(d)0.6
Step-by-step explanation:
(a)Frequency Distribution

(b)The relative frequency distribution.

(c)The cumulative frequency distribution.

(d)The proportion of customers needing an oil change who wait 9 minutes or less.
Proportion of customers needing an oil change who wait 9 minutes or less.

52, i am so sorry this is probably incorrect
4/9 , 2/3, 1/6, ....-2 1/2 = - 5/2
common denominator is 18