At ABC college 40% of all entering freshmen graduate within four years. Among those who graduate within four years, 70% had an SAT score at or above 1,000. Among those who do not graduate within four...

At ABC college 40% of all entering freshmen graduate within four years.  Among those who graduate within four years, 70% had an SAT score at or above 1,000.  Among those who do not graduate within four years, 20% had an SAT score at or above 1,000.  If you know that a freshman’s SAT score is below 1,000, what is the probability that this person will not graduate within four years?