EDIT: I misread—please disregard the below comment.
3.5% decrease.
A 100% increase in speed is a 50% reduction in time.
E.g., traveling 60km at 30km/h takes two hours, but at 60km/h takes one hour.
3.5% decrease.
A 100% increase in speed is a 50% reduction in time.
E.g., traveling 60km at 30km/h takes two hours, but at 60km/h takes one hour.