4. 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 destination?