Marty had a contract to paint peters house for $2,000. marty painted the house and peter did not pay marty (under the contract he was to make payment 7 days after completion of the job). peter was happy with the paint job; he didnt pay marty because peter had lost his job and did not get a paycheck that month. six months later, marty needed money badly. marty told peter that if peter would give him $1,100 immediately, marty would release him from the other $900 owed. peter agreed and gave marty a check for $1,100. on the check, peter wrote payment in full. marty cashed the check. two months after cashing the check, marty demanded the other $900 from peter, and filed a lawsuit. who should win and why?