4. You mn into your friend at the tennis court, and your friend challenges you to a tennis match. You are condent that you can beat your friend, so you propose to wager $500 on the match and your friend agrees. To make extra certain your friend will not back out, you use the phone on your camera to record a video of the two of you agreeing to this proposal. As an extra precaution, you have another friend videotape the match. You win as you predicted, and your friend agrees to pay you within a few days. However, your friend keeps delaying the payment and one month passes. Do you think