Frank, wishing to sell his car, put a sign in its window and parked it on the street outside his house. The sign said: Car for Sale -- $2,000; Enquire at 3 Wood Street, Padstowing 0412 000 000

a. Bill walks by at 8:30 am and immediately calls Frank and offers him $1,600 for the car. Frank tells Bill he will think about it and let him know soon.

b. Mark drove by around 9:00 am and took a picture of the car and sign so he could show it to his daughter. That afternoon he posted a cheque for $1,950 with a note saying he would pick up the car on Friday at 6:00 pm.

c. John was walking his dog at around 10:00 am and saw the car and the sign. Using his mobile phone, he searches for Frank's contact details and then emails him: "I accept your offer of $2,000. I'll bring cash Thursday evening and pick up the car". John's email was sent at 10:23 am.

d. Meanwhile at work, Tom, a work colleague, offers Frank $1,700 for the car. Frank promises him he'll accept it if he doesn't get any better offers by the weekend.