Schwartz Brothers Inc., a Washington music merchandiser that operates the Harmony Hut chain, reported higher sales and profits for the quarter and nine months ended Sept. 30.

Third-quarter profits rose to $53,934 (7 cents a share) compared with $28,563 (4 cents) last year. Sales increased to $7.5 million from $5.7 million. For the first nine months, Schwartz earned $101,716 (13 cents) on sales of $19.7 million compared with profits of $59,711 (8 cents) and sales of $16.2 million in the same period on 1976.

President James Schwartz said the improved results reflect higher volumes for both wholesale and Harmony Hut operations, including the London Records line which Schwartz began distributing this year.

New Harmony Hut stores were opened recently in Rockaway, N.J., and Philadelphia.

Hotel Investors, a Kensington real estate investment trust, reported earning in the first fiscal quarter ended Nov. 30 of $614,206 (40 cents a share) compared with $491,739 (32 cents) a year earlier.

The trust said it experienced improved operating results at most properties in which it has an equity interest, particularly a Marriott inn in Dallas, which recently expanded to 447 rooms. Directors approved a quarterly divident of 42 cents a share payable Feb. 1 to stockholders of record Jan. 16. Penril Corp., a Rockville supplier of data communications equipment, reported record earnings of $225,493 (17.5 cents a share) in the first fiscal quarter ended Oct. 31 compared with $170,111 (13.5 cents) a year ago. Revenues increased 26 per cent to $2.8 million. General Kinetics Inc., a Rockville manufacturer of magnetic tape and electronic equipment, reported earnings in the six months ended Nov. 30 declined slightly to $274,537 (37 cents a share) compared with $280,460 (38 cents) last year. Revenues increased to $1.65 million from $1.5 million. Virginia Electric & Power Co., in its monthly earnings statement, said earnings per share in the 12 months ended Nov. 30 were $1.96 compared with $1.71 a year earlier but below the $2.21 of the year ended Nov. 30, 1975.