WASHINGTON POST CO <WPO> 3RD QTR NET Shr 4.77 dlrs vs 1.65 dlrs Net 61.3 mln vs 21.1 mln Revs 312.9 mln vs 291.5 mln Nine mths Shr 9.51 dlrs vs 4.98 dlrs Net 122.3 mln vs 63.9 mln Revs 950.4 mln vs 881.8 mln NOTE: 1987 net in both periods includes gains of 24.2 mln dlrs, or 1.88 dlrs a share, from sale of interest in Detroit Cellular telephone company and 6.1 mln dlrs, or 47 cts a share, from sale of interest in sportschannel Cable programing network.