Could you explain part d) i don't understand the calculations.

\fIn a study on the effect of caffeine on muscle metabolism, nine male volunteers from a random group of men underwent arm exercise tests on two separate occasions. On one occasion the volunteer took a placebo capsule an hour before the test; on the other occasion he received a capsule containing caffeine. The order of these treatments was randomised for each participant. During each exercise test, the ratio of carbon dioxide produced to oxygen consumed (reSpiratory exchange ratio or "%RER\") was measured. The data are as follows: -n"---nnn m-M min-a