The answer should be 7.5 mins, but I may have calculated wrong :/ I hope that helps you come closer in your answer :)
Answer:
a = 24
Step-by-step explanation:
Serving to induct or bring in; introductory
4 Red + 8 Blue + 3 Green = 15 Total Marbles
(4/15) * (3/14) * (2/13) = 0.0087912088
Nearest 1000th = 0.009
Answer: 0.009