you plan to drive north from city a to town b and then continue north to city c. the distance between city a and town b is 39 miles, and the distance between town b and city is 99 miles. assuming you follow a straight driving path, after how many miles of driving will you reach the midpoint between city a and city c? if you drive an average of 46 mi/h how long will it take you to drive from city a to city c?