DEAR BOB: My wife and I together have total gross annual income of $28,000. We were thinking of buying an $80,000 older house. We have $20,000 for the down payment and will require a $60,000 mortgage. But in your recent article, you said lenders recommend buying a home priced 2.5 times annual gross income. Is this for the purchase price or the mortgage amount? We were ready to sign the offer, but now we're worried. Thomas D., Arlington.

DEAR THOMAS: Don't let mortgage lender's guidelines discourage you from buying the home you want. One way or another you can finance its purchase.

A long-standing rule of thumb has been home buyers shouldn't buy a home costing more than 2.5 to three times the family's total gross annual income. That would put you in the $84,000 price range so you're right on target. However, this rule is being violated very frequently due to rising home prices and anxious mortgage lenders who want to make mortgage loans.

But a more important guideline is your monthly housing cost, including mortgage payment, taxes and insurance, shouldn't exceed 25 percent of monthly family income. Depending upon your mortgage interest rate, taxes, and insurance cost, it appears you come close to meeting this guideline.

Many mortgage lenders are stretching this rule up to 33 percent if you don't have other heavy payments or a large family. If you don't qualify with one lender, keep shopping for a mortgage until you find a lender who will finance your home purchase.

DEAR BOB: I am 62 and my wife is 53. We have owned and lived in our home since 1963. If we sell it now, will we qualify for that $100,000 profit tax exemption for people over 55? Paul M., Gaithersburg.

DEAR PAUL: Yes. Only one spouse need be 55 or older on the date of title transfer if that spouse has owned and lived in the principal residence any three of the five years before sale. There is no need to wait to sell until your wife becomes 55 as only one $100, 000 exemption is allowed per married couple. Your tax advisor has full details.

DEAR BOB: I feel that you should emphasize that mortgages are virtually cost-free today. With property going up in value at least 10 percent terest is cost-free. Jack M., Annapolis.

DEAR JACK: Thank you for giving me another opportunity to say that mortgages, especially the fixed-interest-rate type, are true bargains even at today's high interest rates.

According to the National Association of Realtors, resale homes are now appreciating at an average annual rate of 14.3 percent. This means if you get a new mortgage at 10 percent interest to buy a home you're profiting and that mortgage costs virtually nothing in interest.

DEAR BOB: In 1977 we sold our home and used what was then called the "over 65 rule" to exempt from taxation our profit on the first $35,000 of our home's sales price. In 1978 we bought a condo. If we sell it in $981, after three years of resident ownership, can we qualify for that new $100,000 profit tax exemption too? A CPA friend says no but my brother says yes. Who is right? Hudson E., Alexandria.

DEAR HUDSON: Your barber is right. The new $100,000 tax nreak is available to qualified home sellers even if they previously used the old, now repealed, "over 65 rule." Perhaps you should look for a new tax advisor as it appears your CPA isn't too sharp on real estate taxation.

DEAR BOB: I would like to buy a home in my name and my daughter's name. But if I should wish to sell in the future, would my daughter have to sign the deed? When I die I want her to receive my property. Margaret R.,Clinton,Md.

DEAR MARGARET: To convey marketable title to property held in joint ownership, all joint owners must sign the deed. If a joint owner refuses to do so, good title to the property can't be delivered without court action. Joint property ownership is no substitute for a valid will which could convey your property to your daughter after your death.

DEAR BOB: We are thinking of giving away most of our properties to our children. Although we don't expect to die soon, as we are in our seventies, we don't have too many years left. Even if we give away our properties, a friend tells us if we die within three years of the gift, the value of the properties given away counts in our estate. True? Sally Mae M.,Bethesda.

DEAR SALLY MAE: Your friend is correct. It's true that property given away within three years before death is included in the value of the decedent's estate. This tax rule is to prevent gifts in contemplation of death which attempt to get assets out of the estate of a person who expects to die soon. Talk to an estate planning attorney who can show you how to minimize gift and estate tax on your contemplated property gifts.