The Washington Post Co. said third-quarter revenue rose 6 percent from the same period a year ago, helped by higher advertising revenue at The Washington Post newspaper. Net income, excluding one-time charges and gains, rose 17 percent in the third quarter, to $59.7 million ($5.90 a share), from $50.9 million ($5.00) in last year's third quarter.

If nonrecurring gains and losses are included, third-quarter profit totaled $51.7 million ($5.10), down from $81.8 million ($8.05) in the same quarter a year ago. The Post incurred a one-time, after-tax charge of $8 million in this year's third quarter from its investment in BrassRing Inc., a new online job search and recruiting business it formed with two partners. Net income for 1998's third quarter included a one-time, after-tax gain of $30.9 million, resulting from the sale of 14 small cable systems as well as the company's investment in Junglee, a facilitator of Internet commerce.

Newspaper division revenue in the quarter rose 6 percent over year-ago totals on the strength of a 10 percent increase in advertising volume at The Washington Post and a drop in newsprint prices. Classified advertising lineage--where The Post faces competition from Internet sites--is down slightly for the year, but was up in the third quarter, said Washington Post chief financial officer Jay Morse.

Operating income increased in the third quarter in the company's magazine and cable divisions but fell in its broadcasting unit because of weaker national advertising revenue.

Washington Post shares rose $5.25 or 1.1 percent, to close at $495.37 1/2.

* Virginia Commonwealth Financial Corp. of Culpeper, Va., said its third-quarter net income increased 6.8 percent, to $1.13 million (56 cents a share). For the nine months ended Sept. 30, net income increased 3.2 percent to $3.35 million ($1.64).

The company, which owns Second Bank & Trust and Virginia Heartland Bank, said the results were positively impacted by a 7.2 percent increase in net interest income, which is the key driver of banking revenue. Negatively impacting earnings was a 6.4 percent increase in operating expenses attributed to growth efforts.

Assets grew 6.6 percent, to $366.5 million.

* GSE Systems Inc., a Columbia technology consulting firm to the energy and manufacturing industries, yesterday announced it lost $727,000 in its third quarter ended Sept. 30, compared with a loss of $2.2 million during the same period last year. Third-quarter 1998 results included a $5 million loss on the sale of assets relating to its oil and gas business unit.

Revenue for the third quarter was $15.6 million, down from $19.2 million during the same period in 1998.

Net income for first nine months of the year was $875,000 (17 cents), compared with $141,000 (3 cents) the year before. Revenue for the year so far was $51.2 million, compared with $53.4 million during the same time in 1998.