Jan 10 (Reuters) - This year's Kentucky Derby will be the richest in history as the purse for the first jewel of U.S. thoroughbred racing's Triple Crown has been raised 67% to a record $5 million guaranteed, Churchill Downs said on Wednesday. https://storage.googleapis.com/cloudstacksos/%20Quick%20Loan%20Pro/%20Quick%20Loan%20Pro/index.html