Sharp as a tack!

 

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 a cup of 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'.