Fourteen-year-old Tiffany Salzer got an "A" on her book report without opening the book. She watched the movie instead.

"It only took me three hours to watch the movie and it would have taken me 12 hours to read the book," said the ninth-grader from Ventura, Calif.Her father, Jim, owner of Salzer's Video Store and a board member of the Video Softwares Dealers Association, is familiar with the situation.

"It's a problem," he said. "A kid essentially can rent a classic movie and do a book report from it. Kids are taking shortcuts."

Videotape retailers across the nation say many teenagers, children of the television generation, are taking study guides that summarize literature one step further and turning to videotapes for help with homework, renting rather than reading.

Tiffany said her teachers sometimes show movies in class, but only after students presumably have read the corresponding literature. She said she watched "Clan of the Cave Bear" the night before a report on the book was due.

"The teachers say the movie is different. Sometimes it is, but students don't really care," she said. "It's better to get a `C' than an `F.' "

At parents' requests, Art Marra pulled "To Kill A Mockingbird" from the shelves at his HTO Video store in suburban Pittsburgh after students were assigned to read the book.

Since then, Marra periodically has refused to rent certain videotapes to youths because he learned the corresponding books were homework assignments.

"We're a community-oriented shop. We try to give the community any cooperation we can," Marra said.

Mike Petraglia noticed young people make sporadic runs on certain films at his Video-O-Video store in Pittsburgh. He said a popular videotape among teens is "Dirty Dancing," but when assignments dictate, he can't find enough copies of "Death of a Salesman," "Treasure Island," "Grapes of Wrath" and "Billy Budd."

" `Gone With the Wind' has been picking up a little bit. I think it's book-related," he said.

Students always have searched for the easier way, and the video scholar is just a variation of the Cliff Notes customer, said Scott Treibitz, spokesman for the American Federation of Teachers, based in Washington, D.C.

For 29 years, students have used Cliff Notes to provide summaries and analysis of books, and sales of the study guides still are growing, said Doug Lincoln, spokesman for Cliff Notes Inc. of Lincoln, Neb.

"The problem now is with the access of video cassette recorders and with the access of video stores," Treibitz said.

Lincoln said Cliff Notes may produce its own videotapes, but he declined to discuss details.

"The generation that is in elementary school now, they're certainly in the video age," Lincoln said. "I would have to say the (use) of video will probably only increase."

Teachers are increasingly using videotapes in the classroom, and as a supplement the tapes are helpful, said Judi Boren, spokeswoman for the North Allegheny County School District in suburban Pittsburgh.

"You can't use the video as a Cliff Note kind of crutch," Boren said. "There's a saying, `I read the book. I don't need to see the movie.' If you make some comparisons, maybe you need to do both."

"A teacher can give a lecture on the Grand Canyon, Niagara Falls, space exploration," Treibitz said. "A video not only gives that same material, but shows the visuals to reinforce that material.

"It can't replace reading, it can't replace writing, and there are times it can't replace the lecture," he said.