Answer
It costs 13 dollars to power holiday lights for 6 hours.
Work Step by Step
Since the number 6 is inside the parentheses, this means it is a value for h. For this function, h represents the number of hours a day holiday lights are used. For this function E(h) represents the cost of the electricity to power the holiday lights. It is given that the function value equals 13 when h equals 6. Therefore this can be interpreted as "It costs 13 dollars to power holiday lights for 6 hours."