Jackson used 8/9 of a case of soda to fill 1/3 of the soda machine. how many cases does it take to fill the soda machine?

Jackson used 8/9 of a case of soda to fill 1/3 of the soda machine.
how many cases does it take to fill the soda machine = ?
1/3 means three parts of the soda machine, it means if we fill with 8/9 of a case three times soda machine will be full so,
8/9 + 8/9 + 8/9 = 24/9 
it means it takes the case of soda between 2 and 3.
2.667 approx. cases of soda it take to fill the soda machine.

9/12 is the answer because 3/4 times 3 each is 9/12