DEAR ABBY: My parents recently divorced. My sister and I live with our mother. Mom and Dad had to sell our three-bedroom home in the divorce settlement. Even though Dad pays child support, money is tight and Mom can only afford a two-bedroom apartment. This means my sister and I have to share a room after always having our own rooms.

My sister and I have never gotten along well. When we had our own rooms we could just keep away from each other, so we didn't fight that much. However, now that we're in the same room, we can't avoid each other and we constantly argue. It looks to me like she is most of the problem. She always has to have her way and won't compromise. She insists that I'm the problem.

Because we will be sharing a room for the foreseeable future whether we like it or not, can you suggest a way we can live together peacefully in the same room?

"" OREGON SIS

DEAR SIS: It's time you and your sister stopped blaming each other and realized that when objects rub together it creates friction. If you are going to successfully coexist, you will have to recognize and respect each other's space &

regardless of how limited it is. If necessary, divide the room in such a way that you can each have some privacy when you need it. The arrangement may not be pretty, but it could help your relationship.

DEAR ABBY: I work as a cashier in a small grocery store. Many of our regular customers are elderly and live on fixed incomes. Occasionally, I will help customers out to their cars with their groceries, and when I do I am often offered a tip.

My co-workers say it is rude to refuse a tip when someone offers one. I feel what I am doing is part of my job, and I am already compensated for it. Would it be rude to say, "No thank you?"

"" CURIOUS CASHIER, KINGSTON, TENN.

DEAR CURIOUS: It is not "rude" to refuse a tip if you do it with a smile, say that you were glad to help the person, and explain &

as you did in your letter &

that you feel what you did is part of your job and you are already compensated for it. (It is also not rude to ask that person to mention it to your boss. With your exemplary attitude you should make assistant manager in no time.)

TO MY JEWISH READERS: It's time to hide the matzoh &

Passover begins at sundown. Happy Passover, everyone!

Dear Abby is written by , also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Write Dear Abby at or P.O. Box 69440, Los Angeles, CA 90069.