Recently, our party barbarian gained two levels of Exhaustion. As per the rules of that condition (PHB, p. 291), the effect of level 2 Exhaustion is:
The fly spell (PHB, p. 243) has the following effect:
You touch a willing creature. The target gains a flying speed of 60 feet for the duration.
We wondered what the barbarian's speed would have been if fly was cast on him. Which of the above rules would be considered more specific? Would the barbarian be able to fly for 60 feet, or only 30 feet, per turn?