Potato Salad

3 cups cooked diced potatoes
1 Tbsp. finely chopped onion
1 Tbsp. vinegar
2 Tbsp. salad oil
1 hard cooked egg
1 tsp. salt
1/2 cup diced celery (or cucumber)
1/4 cup diced green pepper
1/4 cup mayonnaise
1/4 cup pitted black olives

Place potatoes and eggs in mixing bowl; add onion, vinegar, salad oil and salt; toss lightly. Cover and chill. Add celery, green pepper, olives and mayonnaise; toss until well mixed.