Rising for the third straight session, gold gained 90 rupees, to 28,280 rupees per ten grams at Delhi's bullion market on Monday, on sustained buying by stockists and investors, amid a firm global trend. Silver rose 400 rupees, to 65,500 rupees per kilo.Overseas, gold gained 11 dollars, to 1,894 dollars an ounce, as concerns about slowing global economic growth and Europe's debt worries spurred demand for the precious metal.