Jimmy and his family  are  on their way to visit some family friends who live 
 780 miles away from them. Based on the route they chose, they expect to 
 complete their trip in three days. The distances and average speeds for the 
 first two days driven are shown below. 
 • First day: 4 hours at an average speed of 60 miles per hour 
 • Second day: 6 hours at an average speed of 65 miles per hour 
 If the average speed on the third day is 60 miles per hour, how many more 
 hours will it take for them to reach their family friends’ home?