To find out how much farther Selma has to hike after taking a break, we subtract the distance she has already hiked from the total distance to Electric Peak.
Total distance to Electric Peak: 11 miles
Distance hiked: 2.4 miles
Distance remaining = Total distance - Distance hiked
Distance remaining = 11 miles - 2.4 miles
Distance remaining = 8.6 miles
Therefore, Selma has 8.6 miles left to hike.