twin bothers, collin and cameron get jobs immediately after graduating from college at the age of 22. collin opts for the higher starting salary, $55,000 and stays with the same company until he retires at age 65. his salary doubles every 15 years. cameron opts for the lower starting salary, $35,000 but moves to a new job every few years so that he doubles his salary every 10 years until he retires at age 65. what is the annual salary of each brother upon retirement?