A marketing research company employs a large number of typists to enter data into a computer database. The time taken for new typists to learn the computer system is known to have a Normal distribution with a mean of 130 minutes and a standard deviation of 20 minutes. A candidate is automatically hired if he or she learns the computer system in less than 100 minutes. A cut-off time is set at the slowest 40% of the learning distribution. Anyone slower than this cut-off time is not hired. Find the proportion of new typists that take MORE THAN 170 minutes to learn the computer system.