Just forget it

Three sisters, ages 92, 94 and 96, live in a house together. One night the 96-year-old draws a bath. She puts her foot in and pauses. She yells to the other sisters,'Was I getting in or out of the bath?' The 94-year-old yells back, 'I don't know. I'll come up and see.' She starts up the stairs and pauses 'Was I going up the stairs or down? The 92-year-old is sitting at the kitchen table having tea listening to her sisters, she shakes her head and says, 'I sure hope I never get that forgetful, knock on wood.' She then yells, 'I'll come up and help both of you as soon as I see who's at the door.'