In AV 'ability' is either material (Le 27:8; Ezr 2:69; Ac 11:29) or personal (Da 1:4; Mt 25:15) capacity. The mod. meaning ('mental power') is not found in AV.
He gave one five thousand dollars, another two thousand, another one thousand, to each in accordance with his ability. Then he started on his long journey.
So the disciples decided to send a contribution, each in proportion to his prosperity, to help the brothers who lived in Judea.