The Interstate On-Ramp Is 1

Multiple Choice

The interstate on-ramp is 1.5 km west of your home, and on leaving for grandmother's house you are only able to accomplish an average velocity of 12 km/hr between your home and the on-ramp. At the on-ramp, you wait for traffic for 2.0 min before proceeding toward grandmother's house. If you wish to arrive there, which is 15 km south of the on-ramp, over a river and through some woods, in a total elapsed time of 25.0 minutes, what average speed must you maintain on the interstate highway?

A) 51 km/hr
B) 58 km/hr
C) 67 km/hr
D) none of these