Answer:
18 ATP.
Explanation:
Total 18 ATP are produced because 9 FADH2 are converted into 9 ATP molecules and the earlier 9 ATP molecules are already present in the first b-oxidation process. The first Krebs cycle produces 27 NADH, 9 FADH2 and 9 ATP while on the other hand, the second Krebs cycle produces 9 ATP molecules from 9 FADH2 so total it produces 18 ATP molecules.
We generally say that you get 3 ATPs per NADH and 2 per FADH2, so that these carriers produce a total of 30+4 = 34 ATPs..... and the Krebs cycle itself produces 2 GTPs, which are equivalent to 2 more ATPs, for a total of 38.