at the rate of 6% per annum."
After the trustees' meeting, the minutes were signed by all the members of the board including the decedent, Mr. Timko. Subsequently, on February 21, 1964, the building was purchased by the Association. Mr. Timko dealt with the owners of the property on behalf of the Association, arranged for a bank loan, attended to other closing details, and paid closing costs in excess of $5,000.
*665 On December 17, 1964, Mr. Timko wrote a letter to the president of the Association indicating that he expected to donate the full amount of the building sometime in February of 1965 and that this donation would "clear off all debts". The letter reads in its entirety:
"Dec 17, 1964
"Dear Bro. Moore:
"Received your letter of Nov 19 in regard   "/s/ N. Timko"
After Mr. Timko paid the closing costs, he made no additional payments to the Association toward the purchase of the building after the letter of December 17, arrayed above.
Mr. Timko died on January 2, 1969. The Association filed a claim against his estate for the amount of the unpaid balance on the purchase price of the building. After a hearing on the claim before a probate referee, the Association's claim was denied. This decision was later affirmed by both the Macomb County Probate Court and the Macomb County Circuit Court.
On appeal, the Association asserts that Mr. Timko's promise to pay the unpaid balance of the cost of the building constituted a valid enforceable claim against his estate under either the doctrine of mutual