At 3:00 P.M., a bank robber is spotted driving north on 1-15 at milepost 111. His speed is 148.0 mi/h. At 3:37 P.M., he is spotted at milepost 186 doing 104.0 mi/h. (Assume a straight highway). Assume north to be positive. What is the bank robber's displacement during this time interval? Enter a positive value if the displacement is toward north and enter negative value if the displacement is toward south. mi