The regular price of a child's entry ticket to a water park is $6 less than that for an adult's. the park offers half off all entry tickets during the off-peak season. the sandlers paid a total of $78 for 1 adult ticket and 2 child's tickets to the water park during the off-peak season. the following equation represents this situation, where x represents the regular price of an adult ticket: 78 = one-half x + (x − 6)