Only 1 letter is delivered a day. Mr. Monday receives a letter from Mr. Tuesday on a Wednesday. Mr. Sunday gets a letter from Mr. Thursday on a Friday. Mr. Thursday gets a letter from Mr. Monday on a Monday. Mr. Saturday gets a letter from Mr. Wednesday on a Tuesday. Mr. Wednesday gets a letter from Mr. Friday on a Saturday. Mr Tuesday gets a letter from Mr. Sunday on a Thursday. When does Mr. Friday get a letter from Mr. Saturday?
