A Montgomery County Circuit Court jury, after deliberating for an hour and 45 minutes yesterday, convicted a District man of robbing a wealthy Bethesda couple in a break-in police allege he carried out with his twin brother.

Anthony Andrew Rice, 37, of 4917 Arkansas Ave. NW, now faces up to 115 years in prison for his conviction on two counts of armed robbery, two weapons charges, one count of burglary and one count of theft. Montgomery Circuit Court Judge Leonard Ruben set sentencing for June 10.

Also charged in the Jan. 17, 1984, robbery, but scheduled for a separate trial, is Rice's identical twin brother, Arnold Haywood Rice of 215 Spring St., Takoma Park.

Throughout the trial's three days, Arnold Rice sat outside the courtroom, smoking and waiting for recesses to talk with his brother and defense attorney Patrick Smith. Yesterday, Ruben ordered the jury out of the courtroom and told a marshal to bring him into the courtroom.

"Let's have a look at you," Ruben said to the twin, who stood silently before him. Later the judge ordered that the brothers be fingerprinted to assure that they do not switch places.

On Monday, Harold Reznick, owner of Diener's Carpet and Tile, a chain of seven stores in Maryland, Virginia and the District, testified that he and his wife, who was recuperating from surgery at the time, were surprised in the den of their Bethesda home by two men wearing ski masks and brandishing guns. Reznick said they were tied up for an 1 1/2 hours while the intruders rummaged through the house, looking for cash, jewelery and furs.

He identified for the jury five fur coats or jackets and dozens of pieces of jewelry that belonged to his wife that police said were found in the truck of Anthony Rice's white Cadillac the day after the robbery.

On Tuesday, Reznick's wife, Cynthia, took the witness stand, but Assistant State's Attorney Robert L. Dean excused her after she broke down in tears and appeared too upset at recounting the robbery to continue her testimony.

Anthony Rice's defense centered on his account that he was visiting his sick mother at the Washington Hospital Center on Jan. 17 around the time that the Reznicks were being robbed.