More than half of all the women in this country are working outside the home. The figure climbs to 75 percent if you talk only about women under 35. Obviously this has had a significant impact on life styles, particularly when it comes to meals. It also accounts for the supermarkets' efforts to combat this trend with their emphasis on ready-to-eat foods from enlarged deli counters and bakeries to frozen prepared foods which are often advertised as being just like what you can buy at a carry-out.

"In general," as consumer writer Sidney Margolius reports, "working wives suffer from a lack of time to plan and shop economically." He might have said "working people." The problem afflicts anyone who likes to eat dinner at home, whether alone or with family.

The food industry has taken full advantage of the situation, creating and advertising prepared foods which are supposed to save time. That they may not be as palatable, that they may be less nutritious, that they definitely cost more, is not part of the advertising campaign.

Surveys have found that working women feed their families on a par with full-time homemakers, but often spend about 50 percent more. The extra money goes into more meat, baked goods and ready-to-serve foods.

It doesn't have to.

There are simple alternatives to TV dinners, cold-cut platters, boil-in-the-bag mixed vegetables in cream sauce with toasted almonds, cans of chili, boxes of macaroni and cheese. The alternatives are as good, usually better. They offer a lot more for a lot less and can be ready to eat in less time than it takes a TV dinner to heat.

Weaning yourself from anonymous food prepared by anonymous machines involves a certain amount of reorganization and rethinking.

First you must decide whether or not you really believe the commercials which imply that cooking from scratch is a tedious, time-consuming job for an expert.

Then you have to get organized. Organized enough to keep a few quick recipes in your desk drawer at the office so you can buy any ingredients you will need on the way home that night, or with a good enough memory so that you know what you will need without referring to a recipe.

With that kind of set up you don't have to decide about dinner until you are ready to leave the office.

Finally, you have to be willing to spend half an hour preparing the meal. That's 30 minutes from the time you put on your apron, if you wear one, until the food is ready to go on the table.

Eating the meal doesn't count!

Neither does washing the dishes. But cooking these meals from scratch will require approximately five more pieces of equipment (ranging from pots to utentils) than if the meal had been eaten on aluminum trays and from plastic pouches.

With most of the suggested meals the cook will even have time to set the table, though it would be nice if someone did that little bit. It would be even nicer if someone else washed the dishes.

There are several fundamentals for preparing meals in minutes. The size of the food is important. Chicken in small pieces-- legs, thighs, breast quarters-- takes much less time to cook than a quartered chicken. Pork cubes rather than chops (though thin pork chops cook quickly, too), thinly sliced beef, and ground beef, of course, will cook in a short time, allowing plenty of time to season them with a variety of ingredients. Some vegetables should be cut up or broken into small pieces-- broccoli or cauliflower buds instead of a whole stalk or head. Tiny new potatoes can be cooked in their jackets. On the other hand, it is important to select vegetables which do not require a lot of peeling or cutting. You don't want to spend half of the allotted time, cutting the tips off string beans.

But you can simplify and cut down on certain chores that will not noticeably affect the quality of the dish. When onions are going to be thoroughly cooked, it isn't always necessary to mince them finely. Nor is it always essential that tomatoes be seeded. Coarsely cut green pepper is often just as tasty as minced pieces. (On the other hand, chunks of garlic, when minced are called for, will not work.)

Sometimes recipes call for cooking on top of the stove and then baking in the oven. Often the amount of time on top of the stove cooks the dish completely; baking isn't necessary. If the dish is topped with melted cheese the same effect can be achieved by sprinkling the cheese on top of the ingredients in the skillet and covering it for a few minutes. Or the skillet can be run under the broiler for a minute or two.

Often recipes call for marinating a meat for several hours or overnight. Some marinades are so powerful, the meat will take on the flavors just by being cooked in the marinade. If it is a tender cut it doesn't need the marinade for tenderizing.

These menus and recipes are just a sampling of the from-scratch meals that anyone who knows a blender from a skillet can put together in 30 minutes. They have been tested both by The Washington Post Food Section and by an amateur occasional cook who after making several said: "If I can do them, anyone can." 30 MINUTE DINNERS MONDAY THROUGH FRIDAY

For a 30 minute meal, serve the chicken with Chinese cellophane noodles or rice and red ripe tomatoes with herb dressing. DEVILED CHICKEN THIGHS (3 or 4 servings) 3 tablespoons Chinese or Japanese soy sauce 1/4 cup sherry 1 large clove garlic, minced 1 large slice fresh ginger root or 1/2 teaspoon powdered ginger 1/8 teaspoon hot pepper such as cayenne 1/2 cup water 9 or 10 chicken thighs

Combine all ingredients but chicken in a heavy pot large enough to accommodate the chicken. Bring liquid to boil in heavy pot. Add chicken pieces, skin side down, reduce heat and simmer in covered pot for 10 minutes. Remove cover; turn chicken pieces over and raise heat so that liquid boils briskly for 10 to 12 minutes, until liquid has evaporated. Turn pieces once or twice so skin becomes caramel color. Watch that the pot doesn't burn. Serve the chicken warm or cold. TOMATO AND ONION RINGS (3 servings) 1/4 cup red or white wine vinegar 6 tablespoons good olive oil 1 1/2 teaspoons dried basil or 1 1/2 tablespoons minced fresh basil 3/4 teaspoon dried tarragon or 2 1/4 teaspoons minced fresh tarragon 1/8 teaspoon dried oregano or 1/2 teaspoon minced fresh oregano 3 large chilled tomatoes, thinly sliced 1 small red onion, thinly sliced Salt and freshly ground black pepper

Combine vinegar, oil, basil, tarragon and oregano and whisk well or shake in tightly covered bottle. Alternate slices of tomato and onion in plates and pour over dressing. If time allows, chill.

When Green and Yellow Pasta is the main dish, you don't need more than a salad, such as this adapted version of Oriental Cucumbers. But if you want more to eat, serve Italian or French bread with garlic butter. To make garlic butter quickly, put a clove of garlic through a press, directly into a small pan of melted butter. Mix and spread over cut slices of bread. GREEN AND YELLOW PASTA (4 servings) 1/2 pound spinach pasta 1/2 pound regular pasta 3 cups cubed zucchini 2 cloves garlic, minced 2 tablespoons butter 2 cups plain yogurt or mixture of half yogurt and half sour cream 3 tablespoons chopped fresh basil or fresh parsley Freshly grated parmesan cheese

Cook pasta according to package directions, until al dente. Meanwhile, melt the butter and saute the garlic and zucchini until it becomes golden. Turn off heat and stir in yogurt while pan is still on stove. This will warm the yogurt but it won't curdle.

When pasta is cooked, drain well and stir in yogurt mixture. Stir in the basil or parsley and serve, accompanied by freshly grated parmesan.

Note: Sliced mushrooms (about 1/2 pound) can be substituted for the zucchini. ORIENTAL CUCUMBERS (4 servings) 1/2 cup rice wine vinegar or white wine vinegar 2 tablespoons firmly packed brown sugar 2 medium large cucumbers, peeled and thinly sliced

Combine vinegar and brown sugar. Stir in the cucumbers and mix well. Keep cold until serving time.

If you can find unwaxed cucumbers, they don't have to be peeled, just scrubbed well.

If the main course if beef and bulgur, a green vegetable, like zucchini sauteed with a few walnuts will complete the meal. BEEF AND BULGUR (4 servings) 1 pound ground beef 1 cup coarsely cut onion 1 large clove garlic, finely chopped 8 mushrooms, rinsed and coarsely cut 3/4 cup bulgur (cracked wheat) 1 small can chopped olives 1 can (16 ounces) tomatoes 1/2 cup dry sherry 1 teaspoon dried oregano Salt and pepper to taste 1 cup grated meunster or monterey jack cheese (optional)

Cook the beef in a skillet in its own fat, stirring to break up. Drain off most of fat and add onion, garlic and mushrooms, cooking until onions begin to soften and meat has lost pink color. Add bulgur, olives, tomatoes, sherry, oregano, salt and pepper to taste. Cover and cook over medium heat, allowing mixture to simmer, about 15 minutes, or until bulgur is soft. (If there is not enough liquid from the canned tomatoes to keep mixture moist, add a little water.) About 2 minutes before dish is done, add the cheese, sprinkling it on top, if you are using it. Cover and finish cooking, until cheese melts. Serve, sprinkled with parsley, if desired.

Reheat leftovers in covered pot. ZUCCHINI WITH WALNUTS (4 servings) 1 pound zucchini 3 tablespoons butter 1/2 cup coarsely chopped walnuts Salt and pepper to taste

Wash zucchini and cut into very thin slices. Saute in hot butter until slices begin to soften. If much liquid is accumulated, pour off. Add walnuts and stir to brown and crisp. Season with salt and pepper.

You can put together shrimp and nectarines with egg noodles mixed with poppy seeds and a salad of tomato and cucumber slices with a yogurt dill dressing. SHRIMP AND NECTARINE SAUTE (2 or 3 servings) 1 pound peeled shrimp, uncooked or 1 pound scallops 2 tablespoons butter Salt and pepper to taste 2 cloves garlic, minced or crushed 2 ripe nectarines, sliced 1 tablespoon chopped parsley 2 tablespoons lemon juice

If frozen shrimp are used, do not defrost. If scallops are used, wash and dry. Cut sea scallops into smaller pieces. Leave bay scallops whole. In large skillet heat butter, add garlic, shrimp or scallops, salt and pepper to taste. Cook quickly over high heat, stirring occasionally, until shrimp turn pink or scallops begin to brown, 5 to 10 minutes. Add slices of nectarines for last 2 or 3 minutes of cooking. Add lemon juice; stir and serve, sprinkling parsley over dish just before serving. YOGURT DILL DRESSING (About 1 cup) 1 cup plain yogurt 1 tablespoon finely chopped fresh dill or 1 teaspoon dried dill 1 finely chopped green onion, white and green parts Combine ingredients and serve over slices of tomato and cucumber. Note: Dressing can be heated, just enought to warm through (DO NOT BOIL) and served over vegetables such as broccoli, asparagus, spinach, Brussels sprouts or green beans.

With the fish and tomato mozzarella salad, rice cooked in chicken broth would go nicely, though I have seen the salad eaten inside pita bread instead. The salad can only be made successfully with fresh, juicy, red-ripe tomatoes. FISH BONNE FEMME (3 or 4 servings) 1 1/2 pound fish fillets (blue Rock, flounder) 1/2 cup sliced mushrooms 1 teaspoon minced shallots 1 teaspoon minced parsley Salt and pepper to taste 1/2 cup dry white wine 2 tablespoons butter

Cut the fish fillets (with or without skin) in half if fillets are large. In heavy skillet with cover, place mushrooms, shallots, parsley, wine and butter. Add fish, flesh side up. Sprinkle with salt and pepper. Bring to simmer. Cover and simmer for 10 to 15 minutes, depen1ing on size of fillets, until fish flakes easily with fork. Serve immediately. TOMATO MOZZARELLA SALAD (4 servings) 2 large tomatoes, thickly sliced 4 ounces mozzarella cheese, thinly sliced 1/2 cup shredded fresh basil Olive oil Salt and freshly ground black pepper

Arrange alternating slices of tomato and cheese on a platter. When ready to serve, sprinkle with basil. Drizzle with good quality olive oil. Pass salt and pepper.