A disk jockey must play 16 commercial spots during 1 hour of a radio station. Each commercial is either 30 seconds or 60 seconds long. If the total commercial time during 1 hour is 13 minutes, how many 30-second commercials were played that hour? How many 60-second commercials?
How many 30-second commercials were played that hour?
How many 60-second commercials were played that hour?
How many 30-second commercials were played that hour?
How many 60-second commercials were played that hour?