Carl is incorrect. Dave ate a higher fraction of snack bars, by 0.2 snack bars.
Carl had .5 left of a snack bar.
Dave had .3 left of a snack bar.
Tony had .5 left of a snack bar.
Gary had .0 left of a snack bar.
Tryone had .7 left of a snack bar.
If we add the above snack bars, there is a total of two remaining snack bars, meaning they only ate 12 of 14 snack bars.