Marriott Corp. said strong performances in the company's contract food services and lodging operations boosted profits 17 percent in the third quarter over the same period last year.

Net income from continuing operations for the three months ended Sept. 6 was $44.9 million ($1.67 per share), compared with $38.3 million ($1.44) for the like period a year before. The 1984 results included 10 cents per share related to discontinued theme park operations. Sales for the 1985 quarter totaled $969.0 million, a 16 percent increase over $834.2 million for the 1984 quarter, Marriott reported.

Net income for the year to date totaled $115.6 million ($4.30), up 18 percent from $97.9 million ($3.61) a year ago, the company said.

Lodging operations reported 12 percent higher sales for the 1985 third quarter, while operating income rose 21 percent -- a result, in part, of increases in average room rates that outpaced inflation.

The company also said contract food services recorded a 47 percent gain in sales and 35 percent higher operating income. These results were partly a result of the contributions of two institutional food service companies acquired early in the year, Marriott said.