(i) If number of articles is increasing then cost will also increase. So it is a case of direst proportion
(ii) Cost will also increase when weight of the article is increasing. So it is a case of direst proportion
(iii) Time will increase when distance will increase, if speed remaining constant. So it is a case of direst proportion
(iv) Wages will increase if the number of working hours is increasing. So it is a case of direst proportion
(v) For same distance time taken will reduce if speed is increased. So it is not a case of direst proportion
(vi) Cost for the land will increase if its area will increase. So it is a case of direst proportion