Find values A, B and C and multiply them

A housewife with three young children was getting dinner ready when the phone rang. The six-year-old picked it up and said, "Hi, Daddy!" and she began telling him about her day.
She then passed the phone to her brother and sister as was the custom whenever Daddy called from work.
When it was finally the wife's turn to talk she took the receiver and said, "Hi, honey."
"Thank goodness, lady," the voice on the other end replied. "I just called to tell you that the wallpaper you ordered is here!"